It seems when I have missions enabled with a custom human race, this version is very unstable. But if I don't enable missions, I can play several hours without issue.

Errors have been submitted via the reporting tool:
Clicking the "Comm" Button crashes to desktop
End of Combat Game Freeze
Colonizing crash to desktop

I haven't really experienced those, but i do remember experiencing a 'end of turn freeze' the game itself just freezes, no 'not responding' stuff, just stops.

Have you been playing with missions enabled or without?

It depends,

If i play a non-human race, i tend to play classic mode, but with humans, even customized, i play normal...i wish i could play the crystal bugs or the big rock people, the big probe builder Kortaz or something, their ship models rock big time....wish i could play them.

Anyway, while playing as human i always play with missions turned on, this game will be awesome when its finished.