This little bugger works very well indeed on my hardwood floors! I run it every 2-3 days and it keeps them nice and clean.
Definitely spring for the reservoir pad for it if you are having it do a damp clean, tho - it really improves the quality of the job and you can set & forget it instead of having to pick it up and dampen the pad every 20-30min.
Water works fine, but doesn't pick up oilier residue (like handprints) very well. I'm trying the Bona Hardwood cleaning solution now and it cuts oils but leaves streaks, so I will be trying the Clorox next.
Tip: for extra cleaning pads, just pick up a cheap pack of microfiber cloths from the dollar store, cut them to size & seal the cut edges to prevent fiber shedding (I just used a glue gun). Much cheaper and works just as well as the Roomba brand cloths.
The list of Braava compatible cleaning solutions used to be on the iRobot FAQs, but disappeared for no obvious reason. Here's the text:
Below is a list of recommended solutions you can use with the Braava or Mint Robot
iRobot Hard Floor Cleaner - Use 1/2 a teaspoon per reservoir pad. OR to make a larger batch, use 1.5 teaspoon per quart of water.
Scooba® Natural Enzyme Hard Floor Cleaner - Use 1/4 a teaspoon per reservoir pad. OR to make a larger batch, use 3/4 a teaspoon per quart of water.
Bona Floor Cleaner Products
Clorox "Ready Mop"
The following solutions are NOT recommended for use with Braava or Mint (even if diluted).
Dr. Bronner's Products
Essential oils such as peppermint oil
Anything soapy, such as Murphy's Oil Soap
Polishes or waxes