I'm working on a relatively small proof-of-concept for some line of business stuff with some fancy WPF UI work. Without even going too crazy, I'm already seeing some really poor performance when using a lot of the features that I thought were the main reason to consider WPF for UI building in the first place. I asked a question on here about why my animation was being stalled the first time it was run, and at the end what I found was that a very simple UserControl was taking almost half a second just to build its visual tree. I was able to get a work around to the symptom, but the fact that it takes that long to initialize a simple control really bothers me. Now, I'm testing my animation with and without the DropShadowEffect, and the result is night and day. A subtle drop shadow makes my control look so much nicer, but it completely ruins the smoothness of the animation. Let me not even start with the font rendering either. The calculation of my animations when the control has a bunch of gradient brushes and a drop shadow make the text blurry for about a full second and then slowly come into focus.

So, I guess my question is if there are known studies, blog posts, or articles detailing which features are a hazard in the current version of WPF for business critical applications. Are things like Effects (ie. DropShadowEffect), gradient brushes, key frame animations, etc going to have too much of a negative effect on render quality (or maybe the combinations of these things)? Is the final version of WPF 4.0 going to correct some of these issues? I've read that VS2010 beta has some of these same issues and that they are supposed to be resolved by final release. Is that because of improvements to WPF itself or because half of the application will be rebuilt with the previous technology?