I've got two Roomba Discovery SEs that I've had for about 2 years. They aren't bad, but they aren't the be all and end all of vacuum cleaners. We've got a long hair dog, and while they do a good job of picking up the majority of the hair, it's really a lot more than they can handle. I'd say they are really nice for the occasional touchup work though.
For small bits of stuff I'll pull one out and put it in spot mode. I moved up to a Dyson this past spring. THAT is a vacuum that really blows the doors off of the rest. It's not terribly light, and it's not the cheapest on the market, but it's well worth the investment. Sucks up everything in it's path, and never slows down. My only gripe with it, is that I have to empty the chamber a fair amount due to the large quantities of dog hair. On the flip side, it pulls up stuff out other vacuums have missed. (roomba, and a regular eureka that this replaced)
As far as roomba ability to handle clutered rooms, they do a decent job. I wouldn't call our rooms cluttered, at least not with debris, but the furniture layout is not an easy one to navigate. It doesn't necessarily take the most effecient pass, but it does get the whole room. It's also nice for getting under beds and couches without the hassle of doing it yourself. If you're just looking for a daily upkeep cleaner, you'll probably be happy. don't make it your main one though.
I don't have any experience with the Scooba because it's not compatible with all flooring types. We've got flooring that isn't on the approved list, and didn't want to mess with anytyhing.
good luck
-Jeff
