The S506 is the same as the S500 but with a diferent and in my oppinion a much nicer front bezel!!!
I just built my first system with this case and for the money you cant beat it, lots of room for its size, easy instalation and good cooling with a front and rear fan(although none were included). I thought the 300 watt power suply fan was a little loud though so I swapped it out with a nice quiet Panaflow(much better), I also modded the front metal a little(under the bezel) to fit a 92mm intake fan. I think that the S506 is one of the best looking cases out there, but a little hard to find, I got mine at
allstarshop.com there shipping for cases is high though, but it all ballanced out, cause I got alot of my parts in one order. You can check out the S500 and S506 at
In-Wins site.