I am a regular contributor in the ASP.NET forums. Whenever I get some time free I try to answer ASP.NET related posts. But these days I have become an answer seeker in the MSDN forums (Smart Devices section), as I am working on a Windows Mobile project. The first thing which struck me while registering myself in the MSDN forums was the UI. ASP.NET forums run on the CommunityServer whereas these MSDN forums have been developed by the MS team itself. I was not too comfortable with as I was habitual of using the Community Server.
MSDN forums were also slower than Community Server though feature wise both were comparable (except the latest Community Recognition program introduced in the ASP.NET forums). Another thing I noticed was the absence of any ads in the MSDN forums. But even after this I found ASP.NET forums much more sleek UI wise.
I guess MSDN forums will shift to the Community Server too in future!