Its great and all that 4.1.x is released, but personally I wouldn't upgrade to the latest branch until a few more subversion releases occur. Simply to squish out more bugs as it seems there are more real world bugs unidentified, that only a real world testing environment will identify.
I didn't start moving clients over from 4.0.x until around 4.0.5+ as it seemed to become more usuable in a production environment.
Just my 2cents.
