I had a little go last night, a couple of hours or so, and I'd no issues with it.
Now bear in mind that I don't care about getting a billion frames per second, that really doesn't bother me in the slightest unless it's massively skippy when I turn the camera around. and it's not, so that's fine and I have absolutely no idea how many fps I was getting.
the only bug I seemed to have was that one pop-up seemed to stay on the screen long after it should have gone away, but a quick save and reload made that go away and took about 20 seconds if that.