This is kind of a side-issue, but one of the reasons I prefer Obsidian is that it's free. I would need to pay for a
DDI subscription in order to read about all the latest and greatest enhancements to the core system. Even with the errata the info presented in the
DMG is not enough to make it work for me.
But the main reason I like it is that the 3-round structure prevents having some characters make all the checks while others sit on their hands, which was my main complaint with the core system.
-- 77IM