Here's mine (still in progress, but you can see the enclosed bit of the coop has a waist height floor):
The reasons I went for a raised design are:
1. Less chance of rising damp affecting the coop (we get pretty big dumps of rain during the Summer storms and a lot of it runs overground)
2. Better ventilation
3. Cooler (we have a hot climate and raising it lets air circulate better)
4. Predator/rodent protection
5. Somewhere for the chooks to seek shade on a hot day
6. A shady spot to hang the waterer
7. More floor space in the run
8. Easier access for me to clean/check for eggs etc without having to stoop low
9. The coop doesn't block the view of the run so I can keep an eye out from my window.
and the best reason:
10. My girls have a better view out their window!