Hi
I've been building my own servers since 1997, but now I'd buy a Proliant.
I always chose "best of breed" components like 3Com / Intel NICs over Realtec or others. But still, over the last ten years, clients using Proliants gave me much less hardware headaches than those using my own built servers.
The HP G2 is MUCH louder - and bigger, too! The G2 is much "longer" than average PC's, the G4 is actually smaller than a normal Mini-Tower. The G2 also can hold 4 Disks, the G4 only 2.
The G4 is way better for "quieter" environments like office / home without a dedicated server-room.
One disadvantage of PCs is usually the small ventilators / fans "built-in".
Simple physics: A fan with half the diameter needs to run 4 times faster (!) to keep up with the larger fan. This makes for more wear & tear, higher energy consumption (The fan motors get hot too...) and the worst part: dust and stuff like that usually kills the tiny 1" fans within a year.
My home server had hd-cartirdges, each with a small fan behind. I had to replace those things every few months, as they'ld just die and get hot...
With my HP ML110 G4, I'd just call HP
But then again, this thing doesn't have "tiny" fans - the big ones are WAY more reliable.
YMMV
Andy Wismer