I wrote an article for SQL Mag not too long ago (sadly hasn't published yet) about the differences between the two versions. Have also had several talks w/ the PM for partitioning @ MS about the issues I've seen (issues that Solomon mentioned today about having to do the partition lookup). From the scenarios I looked at, they're exactly the same. The constant scan was removed from the 2008 version of the query plan, but the effect is still the same.

One thing I didn't look into was parallelism. The scenario I was interested in was for an OLTP environment, so parallel queries are something that I was trying to avoid when I could. 2008 does allow for additional threads to satisfy queries across partitions in 2008, but it comes at a cost. This idea could be (and likely is) great for an OLAP environment where you have heave queries that are going to eat up some resources. Throwing all of your available schedulers at the query works great for it. But, it could come back to bite you if it were to happen to you in an OLTP system because it would be possible that available threads are going to go try to satisfy the one query while everything else is holding.