Long-time player, first-time poster here. Just wanted to chime in ith my 1.2 experience.
I've had issues with losing contracts (active and old ones) when adding mods to an ongoing career game, something I've not encountered pre-1.2 though doing it many times. Not sure what that is about, but it is annoying having ten tourists sitting around my space center, five of which are for contracts which the game no longer acknowledgtes that I ever accepted.
Apart from that, only one or two crashes, but my game is fairly well modded (non-parts mods only), so I won't blame that on the devs.
A really good release, in my opinion.