Hi!
MySQL 5.x have been out for a very long time now. 3.5 years of production stable release for 5.0.
Oh! Time flies fast.
Domas, I assume you're still on this list - can you give us some background why we're not on a closer to current release MySQL within the WMF environments?
What would it bring to us? I'm testing 5.4, but need few features to be hand-merged into it to make it more usable for us :)
BR, Domas