Only one problem
The wife and kids constantly fight over who is going to use it. Got it back in November and it has performed flawlessly. Remember they sold over 300,000 iMac G5s last quarter so there are bound to be a few problems - that is what a warranty is for.
Of course, as often discussed here, an update is probably coming this summer and it will also be a Rev B, so if you can wait a few months it may be worthwhile.