Just got my new drives. I RAID them to have one big 320Gigs HD, partitioned them and installed Windows. Everything went smoothly and silently!!! Now, the loudest thing in my case is my PSU!!! As for speed, well, I dont know. Everithing seem faster than with my 2 WD1200JB in RAID too, but since it is a fresh install, well, it is hard to say. but as for noise, well, I had to really listen to them closely to make sure they were spinning at startup...I must say that I'm satisfied with them so far.
-Always put the blame on you first, then on the hardware !!!