It's a port of PCSX, so most of the problems of the PC version are probably there as well.
It comes with a port of the Peops SPU and SoftGPU plugins (no OpenGL yet), and has a custom CDR plugin for CD access (no ISOs yet) and two controller plugins, one for keyboard and one for HID to use gamepads.
In terms of compatibility it should be very similar to the original PCSX.
I made the following tests:
Resident Evil Director's Cut (US)
- doesn't boot.
Metal Gear Solid (US)
- runs perfectly, at least as far as I played (up to the first boss).
Parasite Eve (US)
- no problems after about half an hour of playing.
Silent Hill (US)
- is too fast. The PAL version runs at the correct speed, but seems to have the problem of most other PAL titles I tested...
A bunch of official PAL demos
- Soul Reaver, Tekken 3, Dead or Alive, Rollcage, etc. seem to run quite well, but for PAL the XA sound seems to be too slow and chopped up, which is also noticible in video streams with XA sound. And Tekken 2 has the same weird graphics that almost every PSX emulator produces.
There is a whole lot more testing going on in this Emuscene thread
EDIT: Quoting Gil Pedersen, the author of the port:
I'm sorry to say but the released version of PCSX has a bug which means it won't work under 10.2 until the next release. Expect a new release this weekend or sometime next week.
The problem with XA sound in PAL games can be solved by manually setting the region to PAL.