Lin545: Not updating until most of the mods are ported AND stabilized. IMHO there is no benefit --in--==>
from performance upgrade and fixed part limit bottleneck in Vanilla (unmodded). And 1.1 is basically a migration from Unity 4 to 5, which will require mods to do extra work to port. If you are not on x64 Linux, meaning you had only 32bit executable available - there is little point to use x64 without mods anyway.
GOG is really not the one bottlenecking here. It will be the classy mods.
Edit: The UI floating bubble feature is awesome, click once - and part dialog will be accessible, no matter how fast vehicle starts to rotate. But, with time warp mod it was possible to reduce the time scale to 0.001 to land the click no matter what. So...
ibanix: Over on the KSP forums, even stock players are reporting significant performance gains when doing things like launching ships with high part count.
Most of the modders have been hard at work migrating to 1.1; heck, I have to keep looking for older, 1.0.5 versions. So, it's looking good.
Oh damn, just one simple word written wrong ruins the whole answer :/
Misunderstood. I mean, the delivered performance is not much needed in unmodded installs, and x64bit also not much needed in unmodded installs. It will take significant time to move to 1.1 for mods, due to internal engine changes and squad code changes.
paralipsis: I don't want to be a contrarian, but that's going to be be very much dependent on the individual use case scenarios. Not everyone has extensively modded KSP installs. Personally, I would happily go back to vanilla right now in order to access v1.1.
There is purposely vanilla installs and regular installs. Regular installs are modded. I know features in KSP, which were influenced by mods - like aerodynamics model. Squad are still doing it proper way, they make sure the core is stable and efficient, over feature bloat.
There is little point to install 1.1 on x64 without mods. Typical performance with stock parts was already sufficient except for massive rockets and airplanes, and stations built with regular clampotrons. But again, modded gamers have KIS/KAS, DPAI. KJR etc and need no all-at-once rockets.