I had a go and saw much the same performance as I do with PD 1.5 and no MSAA. Picture quality is comparable though, what it lacks in clarity it makes up for in clean lines and no shimmer so there's something for everyone.
I had a good mess around last night and raising/lowering graphical options don't have affect FPS like I'd expect, despite FPS dips coinciding with periods of high GPU utilisation, so I'm going to try some of the other suggestions in this thread and delete .lua files etc and see how I get on.
Right now it's all just a bit choppy, it gave me motion sickness for the first time in forever.