AetherSX2 is the brainchild of one person, a developer who goes by the handle Tahlreth. The developer actually used the PCSX2 emulator as the basis for their Android-based emulator. PCSX2 is a long-running, well-established emulator on PC, so it makes sense to take advantage of the work...
Look no further then PCSX2, a full blown PS2 emulator for Mac OS X that works surprisingly well. I say surprising because it seems development work is a little infrequent and there are some features left to be desired, but it certainly works and the frame rate is pretty high on my MacB...