2.5 is developing nicely. I find it extremely difficult to go back to 2.4 after getting used to the interface.

We use the latest svn version and build every day. It's comfortably stable. The developing python API has been a pleasure to use, along with being integrated into the interface. I'm looking forward to having the rendering and shading system, dependency graph, Bmesh and animation system completed and given time to mature.

The documentation is insufficient at the moment though. And while 2.5 has made things much more flexible, there is still architecture from 2.4 which restricts full use.

The increase in developers being hired for 2.5 to develop and fix bugs, as well as the 10 GSoC approved projects is a promising sign.