[OT] Looking for a usable UML diagram editor

[solidstate1991]

After StarUML decided to start to randomly crap out on me, while 
potentially ruining my mostly D projects in it by locking them 
into the proprietary *.MDJ format (although it would be easy to 
reverse engineer it, since it's JSON-based). It's also quite 
abandoned as of now, with no hopes of ever improving the constant 
crashes and other issues.

I mainly need one for class diagrams, so that must be a strong 
point of the software, also it would be great if it outputted to 
the non-proprietary *.UML format, so I can include it with the 
source code.