The Qt libraries on Windows have been updated to 5.2.1 which fixes some annoying bugs in the 5.1.1 libs. Specifically, when using e.g move or copy, the shortcut keys to mirror ('x' or 'y') or rotate ('r') did not work. More specifically, they did, but the event filter was getting passed the event twice and so cancelling out changes!
Same for e.g path entry with the 'u' and 'd' shortcuts to switch up or down a layer. And some other weird gui effects. Note on Linux/Mac I am still sticking to Qt 4.8.x as 5.x is either unreliable or will not compile on those platforms without a lot of work.
There have been other general fixes to resolve crashes in certain situations. If you find a crash, please do send the crash stack trace/logfile and (if possible) some data to reproduce it. I can fix 90% of bugs that have data with which I can reproduce; that probably goes down to about 20% for bugs with a crash dump/logfile and even less with just a description of the bug.