I would say its a great advantage registering expired domains with
PR
when you register a expired domain make sure than it had some good back links that will hold the
PR
I have a parked domain which is PR2(downgraded from PR4)
Also I registered another one (PR4)before update it is now also PR4 only
since it got one backlink from a PR4 site
also check the domain at
www.checkpagerank.net to see whether it is a fake pagerank domain!