I feel that. phpBB 3 ("olympus" or w/e they are calling it) looks really nice, but I am thinking about changing over to another forum. I have been talking to some people who said that the upgrade installations are totally blind, so any modifications you have made on your phpBB 2 forum will be totally lost when you upgrade. That practically takes away the whole point of it being open source.
Another forum I am looking into is Simple Machines.