> The P880 and P990 look fine, they have 6 buttons on the right (thinking about
> CPS games), two analog sticks and 2 or 4 shoulder triggers (psx emus).
I have two P2500s, which are pretty much the same as the P880s but with rumble. 880s, 2500s, and 3000s only have two shoulder buttons, so they don't function very well as PS1 controllers, but they do translate pretty well to N64 (surprisingly), Saturn, SNES, Genesis, TG16, MAME, etc.
The dpad on them is comfortable as hell and quite precise while the analog sticks move smoothly and hold center without a problem.
Something you should be aware of about the face buttons is that the rightmost buttons (#5 and #6, or Z and C on a Saturn pad) are smaller than the other four face buttons (as opposed to how the saturn's top 3 buttons were smaller than the bottom three). Also, there's no equivalent to start and select, though that shouldn't pose much of a problem (unless you're trying to do PS1 emulation, which I'd recommend just picking up a cheap PS1->USB adapter for).
On that note, if you can find a cheap PS1 adapter that doesn't induce any noticeable latency, you can also dig around for some cheap Asciiware PS1 sticks. They shouldn't cost you more than $15 or so anymore (though if you look on ebay right now there's one for $8 + $13 shipping...but ebay sellers are good at charging you more than you'd pay in the wild) and they're still pretty dang good (especially for the price).