Actually working out well.
Not sure how to answer to how fast they are. They are fast enough for me as they do everything I need to do in a reasonable amount of time.
Here's what the windows index has to say for primary system.
Processor, 7.2
Ram, 7.5
Graphics, 7.7
Graphics Gaming, 7.7
Primary Hard Disk, 7.3
Main system is very quiet, that is the one with the Seasonic power supply, the Radeon 6850 and the Noctua heatsink and fans, which are some of the quietest, best performing fans I've ever had.
HTPC is somewhat louder, I think it's more to do with the case, which is thin Aluminum and very vented and also quite out in the open. It's certainly not loud and once a show is playing you can't hear it.
At this point I have no desire to move to Windows 8, just doesn't do anything for me. I think MS is making a mistake trying to make an OS that works the same for a tablet as a desktop. Sure make one for a tablet, but I don't see how they couldn't make one tailored to each format.
SeaSonic M12II 620W, ASUS M4A87TD EVO AM3 AMD 870, AMD Phenom II X4 925 Deneb 2.8GHz, Crucial 8GB (4 x 2GB) DDR3 1333, SAPPHIRE Radeon HD 6850, Kingston HyperX 120G 120GB Solid State Boot Drive, WD Caviar 1 TB Storage Drive, LG DVD-RW, Samsung SyncMaster 226bw 21" LCD, Windows 7 Home Premium 64bit