It's about five thousand bug fixes, with a few more welcomed tweaks. 30 max missions in your log, a few specific mob nerfs (not Warnets, unfortunately), plus increased server / client stability & performance. Goodbye memory leak?
Whilst there's no new servers announced, French & German TR installations are at least getting their own language-specific channels, which should clear things up a bit on Centaurus. There's no ETA for when these changes will go live, but let's hope soon.
Full Public Test patch notes can be found here.