I saw them early on this year at Mohegan Sun Casino in Uncasville CT. It was my 2nd time seeing them. Their 2002 show blew me away - one of the best rock shows I'd ever seen, and I've seen tons.
This May 2008 one was very good, well worth seeing, but not quite as amazing. My buddy, an STP newbie, was impressed. The musicianship was excellent, Scott's vocals were good, and he was pretty active onstage, though not the maniac I saw 6 years ago. The light and video show was spectacular. My only negatives were 1) Scott seemed drunk - didn't affect his singing or movement, but his between-song chatting was garbled and 2) lots of dead time between songs -- I assume that's been improved, as I saw a very early show on the tour. They were probably still trying to get used to playing together. No matter - the crowd was VERY into the show, singing along to many songs, and seemed thrilled by the boys' antics onstage.
If you haven't seen them before, don't pay attention to us perfectionist ninnies, and go see them. You will see at worst a good concert, and at best one of the greatest shows of your lifetime.