Good morning! Thanks for you kind comments about my workout room!
My husband researched the flooring before we did this project. I'd been working out on carpet over concrete (ouch -- the knees!) for years in our previous house. I didn't like the way carpet restricted movements (pivots, for example), and the lack of "give," even though it was thick carpet and padding.
The flooring we chose for the cardio area is a a engineered hardwood over a floating system (on a raised grid) with cushioning under the flooring. The floor has a maple finish (light color) -- similar to what Cathe uses in her sets. The sub-flooring helps cushion the shock of high impact and gives you a little extra bounce (unlike carpet).
The floor is easy to keep clean -- I use a steamer with plain water and a microfiber pad. The one thing you do have to watch out for is that the floor will dent it you drop a weight on it. I replaced all of my iron with rubber-coated weights and weight plates.
In the other half of the room, we used rubber flooring. My DH lifts over there and we have a couple of cardio machines and a big weight machine in the corner (I don't think you can see it in the pictures). We felt that it was a better choice for that area, and was less expensive.
I hope this was helpful for you. Let me know if you need more info!