It takes about 45 minutes to do what I could accomplish with an upright vacuum in 15, but it does it every day, and it does it without my help. It dares to go where no vacuum has gone before (under the bed and other furniture). Plus, it's a robot and it's really cute.
Roomba won't replace your standard upright, and you'll probably still pull out the broom for a quick sweep now and then. But if you're used to spending an hour every weekend on your hardwood or tile floors and low-pile rugs only to find them filthy again by mid-week, Roomba will make those in-between touchups a lot more managable and therefore a lot more likely to get done. Get it started in one room and you're free to go dust, do dishes, use the computer, or even leave the house while Roomba whirrs around and picks up debris not just in the centers of rooms but along wall edges and in places you can't (or, let's be honest, don't really try very hard to) reach. A short time later, return to find the floor clean and all you have to do is empty the dust bin. Roomba even sings cheerily to let you know the job is done!
If it sounds too good to be true, it usually is... so here are the "down and dirty" facts as I've discovered so far.
Prep work: Using Roomba requires a reasonable amount of advance preperation, but this in itself encourages you to keep the house clutter free "so Roomba can reach." Obviously, pick up anything small that you wouldn't normally run a vacuum over. Cords should be up off the floor or pressed flat against a wall so that Roomba isn't crossing over them or in danger of getting snagged. It's helpful to collect stray furniture into more condensed configurations, such as pushing a coffee table against the couch to create larger open spaces surrounded by walls rather than an area dotted with smaller obstacles, however this is recommended for most efficient performance and is not necessary for Roomba to operate. Especially not if you're running Roomba every day. You might for example want to pull out dining chairs so that Roomba can clean under the table without too much bumping around, but this could be done maybe every second or third day when a mess becomes noticable.
Area rugs should be tested on an individual basis. Small rugs with fringe are best set aside for the duration of Roomba's venture. Other rugs seem fine as long as they lay flat. Roomba tends to roll over the corners of the rug and a lightweight material might bunch beneth the wheels, causing Roomba to turn away or become trapped.
Obstacles: Roomba employs deliberate obstacle-avoidance manuevers when it encounters a barrier which involve either turning 180 degrees and heading back the way it came, attempting to swing around a corner and continue onward, or moving forward a bit and searching for an exit further ahead. Using a combination of these methods, Roomba will circle completely around chair legs or standing lamps and even sweep under desks or nightstands as part of it's standard cleaning cycle. Roomba's cliff-sensing feature has worked flawlessly in my home so far and the little guy has has yet to take a tumble down the stairs.
Roomba really can go just about anywhere, and thus gets itself into some pretty interesting spots. My recommendation is it's better to be safe than sorry when it comes to defining obstacles or potential hazards (or just things you'd prefer to avoid sucking up). This goes back to room preperation. Assume that Roomba can and WILL travel everywhere, and clear the path accordingly. Should anything prove problematic, Roomba is amazingly adept at freeing itself via a variety of methods that it employs one after another until it has knocked itself loose. Failing this, Roomba will eventually shut off to avoid burning out the motor and emit a sad cry for help that will tug at your heartstrings and have you running to the rescue. So far I have seen Roomba get partially on top of various items, wedge itself under the TV stand, and take a mad dash across a minefield of tangled wires and Roomba rarely needed my intervention to free itself. Ironically, the worst episode was when Roomba ran over the cord from its own charger, which I'd carelessly left sitting out after I'd unplugged the unit earlier. It did indeed manage to try to eat the ONE THING I hadn't removed from it's path...
Roomba does not deal well with rug fringe. The instruction manual says that fringe may be tucked under, however this does not prove useful in all circumstances. Better to pick up small rugs if this is an option, and perhaps block access to rooms with larger fringed rugs if you plan to run Roomba while you're away.
Pickup: I'd rate Roomba's pickup to be fairly high on hardwood and tile, slightly diminished (but still certainly acceptable) on medium- and low-pile rugs or carpet. The main issue isn't Roomba's capacity to suck, but whether certain areas are covered at all. Though it does not do quite so thorough a job as I might with a standard vacuum, again I point out that Rooma is meant to maintain the house between regular cleanings. If it misses a spot one day, chances are it will be back the next. I'm pleased to find that it picks up well enough to keep the place looking like it's been freshly swept and vacuumed for the whole week instead of looking that way for only a day or so otherwise. I do still plan to perform "normal" cleaning on the weekends to keep things from piling up where Roomba can't reach (such as in corners), but at this rate, I wouldn't be surprised to find that I really don't need to do that more than every other week or even less often now.
Roomba is especially suited for cleaning the miniscule daily amounts of dust and pet hair that, left to their own devices, accumulate into little "tumbleweeds" that float EVERYWHERE over hardwood and tile floors. I honestly never realized that a thin coating of filth was responsible for making our floors look dull even after surface dirt had been removed. Well, they DID look dull--now they shine all the time! I didn't know they had it in them! That in itself would make Roomba valuable to me even if that all it did. But it's not: your typical crumb-type dirt, litter, and little bits of whatever-that-is are in the bag, er, the bagless bin, too. Roomba does a GREAT job of cleaning around the baseboards under the kitchen cabinets, where food particulates inevitably end up after being brushed off the countertop. The dust bin has been completely full every time I room Roomba, even when the floor looked clean to begin with. It even vacuumed under the bench in the coat closet and went under the bed...
Provided Roomba runs it over, it'll probably be sucked up. Thus, the worst pickup is near the transition areas, such as a move from hardwood to area rug. Roomba tends to miss debris around the edge of a rug because it's little rollers are half-on and half-off rather than level. Unlike someone running a vacuum or sweeping manually, Roomba can't pick up the rug to get that little line of debris caught along the edge (not yet, anyway!). Also, on occasion Roomba gets momentarily caught while trying to make a surface-type transition and leaves a short trail of Roomba excrete (dust bunnies) behind it when it does manage to wiggle itself free. Most of the time it sucks this up again on the return pass.
Maintenance: I've emptied Roomba's dirt bin after every use and so far it has always been full, but not grossly overflowing to the point of eminent disaster. Some reviewers on Amazon mentioned that they had to empty the cup several times per room, but they must be expecting Roomba to pick up after their "special needs" preschooler's class birthday party because my floor is certainly far from spotless and the capacity has worked fine for me. But emptying the bin can be messy. I haven't yet managed to remove and dump the contents without creating another little pile of dust on the floor. Which I then sic Roomba on afterwards, so that's no big deal.
The instruction manual recommends a detail cleaning of Roomba's innards after every 3-5 uses. I did this after three and was amazed at how well Roomba had continued to function despite it's poor underside being absolutely bound up with hair around every roller, and packed with fur and dust in every crevice. The filter was caked with filth. I will remember to check the state of the filter and rollers more often now that I realize how quickly mess can accumulate there. The actual cleaning process went smoothly. Roomba comes apart easily and snaps back together the same. I didn't even have to refer to the instructions to do this. The tool iRobot provides to clean the rollers also worked well.
Accessories: Roomba Red is the bare bones model, which includes the unit itself, standard wall charger, one virtual wall, and a cleaning tool. Any and all additional accessories can be ordered separetely. Perhaps the two most useful--the remote, which allows you to steer Roomba, and the self-docking charger, which allows Roomba to plug itself in when it's done cleaning--can be purchased for $20 and $60 respectively and will still save you money over the step-up package. The next cheapest bundle includes the remote, self-docking charger, and another vitual wall. IMO, the virtual wall is moot. You can accomplish the same thing with a REAL barrier, even if it's just a paper bag you stand up in the doorway (it doesn't take much of a bump for Roomba to turn around).
Observations: Left unattended, Roomba will spend a disproportianate amount of time in alcoves, entryways, and narrow passages as it ricochets between the walls. It's really good at finding it's way INTO these areas, not so good at getting out. When it actually does find the exit after randomly bouncing around for five minutes, it often pivots and heads right back into the same space on the next pass only to spend another five minutes cleaning this "new" area. As indicated in the manual, it may be a good idea to confine Roomba to larger spaces through use of the virual wall (or a real blockade of some kind) or place it in the specific areas you want cleaned most heavily before setting it free.
It hardly seems fair to write a (mostly) glowing review after only having Roomba for less than a week. For now, I am enthusiastic and impressed. Rest assured that I will update as I see fit!
