Great? Oh god no!! You only remember it as great because at that time it was the only one portable device that could do emulation. But the emulation was not great especially not the SNES.
The single analog stick made devs get creative with moving the camera. That's probably most of the "uniqueness" with PSP games, at least 3D ones. It's also how I found peace in "the claw".
PSP was the best handheld,didn't care that much for Vita since it didn't end up getting the same library but playing the MGS collection on the go was pretty cool. Biggest regret is selling my PSP and all the games just to get money for the new console.