Well, I have owned (still own) only two apple computers:
A Pismo bought new w/ Apple employee discount in 2000, upgraded to G3 900, 7200rpm HD, max ram...had a VERY hard life, still looks new (a little dusty) and performs well, in fact better than new (due to upgrades).
A Quicksilver 733 (bought used off a friend)...never a day's problem either, although it has had a much more protected existence under my desk...
Neither has had to go to the shop, or been down for more than a day...what more can you ask?
From second-hand opinion, I would have to say the PM dual 533 (or 500, can't remember) seems highly recommended by those who have owned them FWIW...never had one myself.