yes they are spendy but.. I can tell you from experience they last a long long time with very little upkeep (kinda like a 22RE.)
I Have had Apple computers since I was a young feller. II E's, 5200,s G3's etc. I bought a G4 Power Mac when I started college. I used that computer every day for 6 years and never NEVER had one problem. I reinstalled the system software one time to freshen it up. On my old G4 I zeroed out the system and reinstalled with 10.5.2 and gave it to a friend of mine who is using it to this day (internet, email, Word documents etc.) and it is STILL strong as ever.
I recently bought a new I Mac 24" which I absolutely love
IMHO these machines are the best!