Look for recycled rubber to be nice to the planet. Here's more on recycled rubber:
Look into the specific product's ability to resist scratches. Sometimes just sliding things like a table along it will leave nasty marks that are tough to get rid of.
Put down cement and wear rubber shoes? Steve nailed this answer.
What did you have in mind and where are you thinking of installing it? Kitchen?
We are working with a charity to remake a BR for a boy with CP. The floor is uneven, so I was thinking this may have some sort of cushioning and hide some of the imperfections. It also offers some color options to do some fun design. I am concerned about off-gasing, odors, etc. If anyone has other ideas on a good product (we are on a low budget), I would welcome ideas. Thought about sheet vinyl, but fun color options aren't great.
So AWESOME! I've yet to install rubber flooring other than in a garage so I tried to do some research. Aside from scuffs from sliding heavy furniture , I couldn't find any drawbacks. There are a ton of different styles and types to choose from and you might even be able to get a donation from a supplier given the nature of your project.
These folks seemed to have a good selection: http://www.floormatcompany.com
Please let us know how it turns out and thanks again for doing what you do!