Has anyone upgraded their OS X servers to Yosemite and Server 4.0? I dealt with a lot of general Netboot flakiness with 10.9 (which has finally stabilized) and wanted to see how 10.10 was.

Though I generally subscribe to the "If it isn't broken don't touch it" school of thought I try to keep the OS X servers up to date because the most recent releases are the most well supported by Apple.