Just got my G5 today. Doing pretty well so far
Transferred all my data from the other networked PC's, Synchronized my mobile with a bit of a struggle using iSync and found some pretty useful software that will sync to Entourage as well - you may know about this already... www.pocketmac.net/products/gobetween/indexg.html

I also found an Outlook to Entourage transfer tool [which I can't buy yet, because Paypal doesn't support South-African CCards] but I'll find someone who can help me buy it.
www.littlemachines.com

I see that you had the same issues with transferring, but the discussion thread seems to have stopped earlier this year - has anyone found a way to keep networked Outlook and Entourage synchronized after an initial transfer?