Congratulations Jeff, it's a beautiful lens and your "can't wait to try it out" mushroom shot demonstrates that perfectly.
I'm very pleased that I paid the extra for the IS L-series version. People need to realise that this not only a macro lens, but an extremely capable portrait lens too. This is where the IS is really useful to me.
As for always using a tripod for macro shots - I spent 30mins yesterday chasing dragonflies around my garden - they move a lot faster than I could ever move my tripod
Again, IS gives that extra little bit of security, though admittedly, not on the Z axiz - that is what AI servo helps with.