I'm impressed with the performance. It seems pretty decent, definitely seems better than the old SNESStation that I think was a port of SNES9X. Certainly not perfect but seems usable. Judging by the performance in certain titles I don't think there is much room for emulating SuperFX or SA-1. Still quite a nice addition to what you can do with your PS2.
Update: I only tried once but has anyone else noticed it seems like it can't load files from DVD-ROM? It does load fine from a CD-ROM. I was trying it out on a DVD-R to see if ESR would be able to run it but it failed.
Edit to avoid double posting:
So i was browsing the source code to SNESticle and no one seems to have mentioned this but the emulator also supports NES games. I didn't extensively test to see what mappers but it loaded Mega Man when I tried a ISO in PCSX2. So that's pretty cool. I'll have to try it out on a real console and see if there is audio support as I don't get any audio in PCSX2 with SNESticle.
It also looks like there may be Famicom Disk System support.
Update: The NES support has audio. It supports atleast mappers 0, 2, 4, and 5. Does not support mapper 69. It also might not support SRAM saves. I tried Legend of Zelda and it did not save the SRAM like it does with SNES titles.