The IS will be nice for anyone using this lens without a tripod and the video crowd will dig it, and it's the only Canon UWA zoom that's ready for a higher resolution camera. It's reasonably priced. What's not to love?
What's not to love?
The price of course! It should be cheaper by $200 - $300
Will the street price drop over time? Hard to say but for a lens that is reviewing so well, why would anyone feel the need to drop the price? People want it already at the current price!
I would be surprised if this lens was discounted much for the foreseeable future (a year or two). Until Canon comes out with a new f/2.8, this is the only UWA that can hang with the 24-70ll and the 70-200ll. It also has a much more reasonable launch price than those two, and particularly the 24-70IS. That's why I jumped on the Canon introductory discount and pre-ordered it. That, and the million lens T-shirt.