I just put one together, fast as hell.... I have a KR7A, 2200, 1gb ram, Leadtek TI 4600 and the NF7-S has a 1900, 8X OTES card TI 4200, and it is just as fast as my 2200 box!
The 8X seems to amke a big diff in video performance, the TI 4200 8X pulled 225 MB/sec on pcpitstop, where my 4X TI 4600 pulled 148.
It seems to be running really well. SO far I would highly recommend the NF7-S. Right now I am just dealing with 1 beep code right at start-up, not sure if that is normal, and cant seem to find a solution yet. (see my post below).
Good luck with your choice