Okay, All my three 5.x Machines are running 5.2-BETA now.
5.1 was released on June 9. It was a huge improvement over 5.0 which had several problems that bite me, like a broken xl(4) driver that made it unusable. 5.1 worked for half a year on my main Workstation and no major problems prevented me from being productive. Although le tried to use it on the univie newscore, and found several problems under heavy load.
Hopefully 5.2 will be as stable. Before Codefreeze CURRENT was quite unstable due to several last-minute commits. But after a week in Codefreeze it feels usable again.