Logic Board replacement success?

My brand new PB 15" 1.5 ghz had to go back to the shop and get a new logic board. I was wondering if anyone has had a Powerbook logic board replaced successfully with no problems after. I have a feeling that this pb might just be a lemon and cause me problems? Am I being pessimistic?

Thanks

Also, it seems to be taking apple a long time, they are waiting on the part coming in, shouldn't they just have those laying around?