To be honest since building my own systems they've been the most reliable pieces of kit I've worked on, especially when cleaning them out.
My first SB75 is 5 years old now I think, still running 2 samsung disks in raid0 which have had some teething problems, not sure if it was the cable or overheating but the array would fall over randomly, lose a disk and I'd have to restart. This is probably because the rear fan was always set to low so not enough air was getting around. (graphics card was also passive with the heatsink inside the case and the NB chipset replaced with a passive zalman) The 220w PSU was also replaced with a 250w for silence, original PSU still works.
Second SB75 was bought off auction and was DOA, much to my annoyance, instead bought a SB61, swapped the motherboards over and used as a media centre. Unfortunately again having the fan on low meant that the 2 1tb drives were getting toasted. I'm using 2 chassis now with the disks in one and the kit in the other, even with a 3ghz HT processor and x800xt it can just about handle 720p content smoothly. It looks a mess but it's all hidden in a tv cabinet.
My friend has a 4 year old SN95 still running on original kit no problems at all. His 6800gt "died" (overheated) but thats because it was so full of dust the heatsink was solid and no air was being moved. After cleaning it worked no problems.
Like most systems, you either have high performance or silence, my low powered shuttles are near silent (disks spinning) and my old kit is still running fine. Would still be using it as a main pc if my family didn't need the parts for needed upgrades, didn't fancy running cad on a celeron.
