The new Mac client is a catastrophe. Which, incidentally, also cost $60. Fundamentally, this stems from it being a fairly lazy wine port.
It is slow: at the lowest settings, I get 20-30fps with lots of stuttering. (At the highest it's actually not much worse — with the stuttering, it's annoying either way).
Yes, I meet the requirements. No, this is not an intrinsic feature of mac gaming (slightly slower? sure. only barely playable? no.).
The patcher is awful. It hung completely once. It doesn't render the progress bar correctly; sometimes it just doesn't render anything at all and you just get a black rectangle. You can still
click on the rectangle, though; it seems to be strictly a rendering error.
The quality of the in-game rendering is abysmal. For instance,
the ground here is missing.
It's unstable. It's crashed multiple times without me even really trying to do anything. (The built-in crash reporter then
also failed.)
Full-screen mode is broken. It successfully takes over all screens (in violation of Apple's recommendations, but I'll let that pass because it was at least listed as a known issue), but then the rendering is offset such that it only fills some portion of the screen. You can't see the missing parts, and you just have black on the other side.
The controls also don't work as I might like (I use one of those mice with a numpad on the side — modifier keys on the keyboard don't do anything if I use the buttons on the mouse). I'm willing to believe that's not SE's fault, though.
All in all, this is about the behaviour I'd expect if I just stuck the game in wine and crossed my fingers. It would be deeply questionable if this were a free addon, and is completely unacceptable for something that costs an extra $60. It's not just me — there are a few reports of this around.