How well does the PSP emulate the Playstation?

Perfectly. The software emulator included in the official firmware is near-perfect and runs everything at full speed, even when scaled to the PSP's resolution.

yea pops is pretty damn good, the problem is finding the games you want to play. big fan but i find a lot of old games are better off as memory than revisiting. then again devil dice is still as good as it was for me day one.

I'm using Pops to play Final Fantasy series and Jojo only.

Is PSX on PSP worth purchasing a PSP for?

Depends on if you like RPGs or not :/

The PS1 era was my least favourite in video gaming history so colour me biased when I say no, it's not worth it.

Oh contrare, I love RPGs. =)

And I would like to play PSX games on the go.

Are you crazy? Don't you enjoy RPGs?

Some people find JRPGs too tedious and overly flashy with little actual substance. At least that what I've been hearing.

I don't have a problem with them being overly flashy but they do lack substance, their storytelling is poor and overdrawn and generally the gameplay itself it pathetic. Turn-based RPGs generally fail in my book. Doesn't help that the PSX library is full of them.

Also going from decent 16-bit 2D graphics to piss poor 3D didn't help my likedness for the system either.

Well, i don't like the system overall but it did give me games that I love like Jojo, FInal Fantasy, Tekken etc etc.