Smooth sailing here. The only real issue I have encountered is a long render time for the Boris CC film effect. Everything else goes much faster. Noticed the same thing in Motion as well so it could be the effect itself or I am missing some setting.
I find that 10.1 is much faster, more responsive and much more stable. Motion does have its occasional moment but seems to improved there as well.
I will say that Final Cut Pro launches must faster than Premiere Pro even thought about. Of course being on an older version might be why this is.