I asked about this too, but in the cleaning forum. Do a search for Roomba over there and you'll find some info. Also, check out Amazon's reviews. I never did get one. Just wasn't convinced one way or the other.

I have a Roomba. It works quite nicely on tile. I figured out after a few attempts that it does NOT work so well on plush carpeting, it kept getting stuck under a bed and picked up a lot of fibers as it's really more of a sweeper than a vacuum. All of my house is tile except the three bedrooms, so I set up a couple virtual walls to keep it out of those areas. The dirt cup holds quite a bit, but the little suction filter is very small, must be cleaned after each run, or every 2nd run at the most. Some of the parts are a bit flimsy and fragile, but they're OK if handled carefully when cleaning it. The docking station and scheduler is nice for programming it to run unattended a couple/three times per week. It doesn't get fully into corners, but it does run along baseboards. Corners can be either done occasionally with a traditional vacuum ... or sweep corners out into the room before a run whenever needed. Some adjustment of room furnishings may be needed to allow space around things and avoid the potential for getting stuck in some situations or possibly knocking over very lighweight nicknacks.

I can't live without my roomba! I have one of the higher end one from Hammacher Schlemmer. It is pricier to buy from them, but they have a wonderful lifetime warranty for exchanges when broken, no questions asked. I've already replaced both the roomba and the dirt dog when the electronics started to act up. Probably it could have been fixed if I called Roomba support and troubleshooted with them, but I like this method much better. The dirt dog is only a sweeper, not a vacuum, but it does a great job on my family room carpet, and picks up a lot of debris. I definitely need to plan a roomba recharging unit in my new kitchen!

What is a "dirt dog" and what is the difference in machines?

Only if she has a whimsical sense of humor since they are little more than mechanical pets. The most useful one I saw was on Youtube with a kitten riding on it.

The dirt dog is a sweeper made by irobot. It is significantly cheaper ($100-130 cost) than the roomba vacuums and are made for workshops, garages, and decks. However, it did such a good job on my family room carpet that I use it regularly for the leaves and dirt that the kids track in, run the roomba vacuum only once a week for the deeper dust.Google irobot dirt dog; it does a lot for a little price.

I had a Dirt Dog for my garage. It is basically a sweeper that sweeps dirt into a little dustbin. It swept up leaves and pine needles very well. Dirt and dust coated and obstructed the exposed sensors quite readily, then the machine stopped running and started beeping. You have to take it apart, clean it out, and blow the dust off the sensors with compressed air. Mine did this about every 15 minutes and it literally took 3 days to vacuum my garage because of all the cleaning and resets it required. I talked to their customer service multiple times and they finally offered to send me a new Dirt Dog but admitted that I would have the same problem with a new one. I finally threw it out because it was such a time-waster.

I'm really confused. NEED HELP DECIDING. It will be used in a cottage where there is mostly hardwood floors and tile. Because there is a lot of sand outside, I want to alleviate a lot of sweeping. Also we cook a lot so dropped food is a concern. I found and bought the 530 model but I'm not sure now if this model is better for carpets and wouldn't work well for my purposes. Maybe I should look into another one, if so, which one? I don't see any called "dirt dog".

just get vacuumn out do it ,put away,alot less hassle,I charge it ,,it hits backs up turns backs up turns over and over ,runs about 20 minutes stops,she says empty I do, it runs 10 min its done...

Works fine on wood floor and tile as long as you don't have a lot of area rugs scattered about. It will take much longer to vacuum a room than you would just doing it yourself with a regular vacuum cleaner. I would guess 20-40 minutes to complete a living/dining area, depending on the size. It's not as loud as a reg. vacuum but there's still noise, which after 20-40 minutes can begin to grate on your nerves.

I think the best application for one of these is for someone who is mobility challenged. If you are able bodied, it's just much easier and more economical to get out the vacuum and get the job done in 5-10 mins.

here's the dirt dog link.

Here is a link that might be useful: dirt dog link hammacher