Floating Floors (among other pros/cons ...): Easiest to install, quick to install, have a 'hollow sound' to them when you walk on them, are soft-feeling to your feet, inexpensive, targeted to DIYer. Glue-down Floors (among other pros/cons ...): Easy to install, quick to install, sound a bit more 'solid' underfoot when you walk on them, feels like a 'solid floor' underfoot, inexpensive, targeted to DIYer.
Here's an article at Today's Homeowner that makes good reading. DO realize the article is 3 years old. There are Engineered Flooring products out there too. They're also glue-down and floating floors too except they can be made of layers of 'real' solid wood as well. I will add as an aside that you can't go wrong either way unless you have a relatively serious moisture issue with the slab. The 'real comparisons' come in when you're comparing solid engineered and solid 3/4" strip/plank flooring to flooring such as Pergo or other acrylic / plastic laminates. (The former may be refinishable whereas the latter can't be.)
If you need more particulars, post up. My best to ya and hope this helps.