Duke of URL just finished a review/overview of XFree86 4.0 for *NIX-based systems. The review covers more on the Linux side but should give some valuable info. It's a possibiliy that this may help some people decide whether or not to go for 4.0 or stick with their 3.3.x X Server.
FULL STORY @ DUKE OF URL (http://dukeofurl.n3.net/reviews/misc/xfree8640)
