SNES is actually not that good on PSP. Yes it has transparencies and emulates the special chips (slowly), but it can't touch the speed SquidgeSNES has now.
I don't know if anyone has mentioned this yet, but SD is also a much better and cheaper format than MS Duo.
Snes on the Psp not that good?
It is great and apart from great speed, it has many features for example:
Save states allowing you to delete, save, import and export to Snes9x state. Autosave timer. The option to completely redefine your controls. You can switch from Video modes of Zoom 4/3, fit, 1:1, Zoom wide, full, full clipped and smoothing.
You have speed limit /fps switch, frame skip, vsync, render PAL as NTSC, gamma correction, screen caliberation, sound frequency and APU cycles ratio, configurable CPU clock speeds, Hack/Debug support, Cheat support like Game Genie, Action Replay, Goldfinger.
Not only this but it has very high compatibility and also runs many of the enhanced Snes games for example Legend Of Zelda Parallel Worlds and Super Metroid Redesign. Considering this emulator is a port and not coded from scratch specifically for the Psp it is even more of an accomplishment.
So unless SquidgeSnes is also a port the speed comparisom isn't fair even though Snes TYL kernel mode runs fast and with the correct settings, many games run full speed or extremely close. The kernel mode version of Snes TYL has a good speed improvement because it uses the Media Engine for all sound processing thereby leaving the main CPU with less load and more time.
Edit: I almost forgot to mention that Snes TYL's most latest version also has a Netplay mode with Wifi support so for example, you could play Street Fighter 2 with a friend against eachother in two player mode. There is also a final release planned so who knows what other improvements there will be.