I know I'm late to the thread as you've already bought one, but still...
Okay as someone who has owned a lot of these I can tell you which one I'd choose every time for everything that doesn't require an up to date firmware.
PCH-1000 (PS Vita Phat WiFi Only)
It has the best screen and it's slightly lighter than the 3G SIM card model - the PSPs and the Slim Vita just don't compare, each and every one of those cheap LCDs are not good enough. Here's my synopsis.
- PSP-1000: Way too dark and has ghosting issues. Even with CFW to unlock maximum brightness when on battery, expose it to even mild daylight and you get eye strain. Shame really, as it's the nicest PSP in terms of build quality, doesn't feel flimsy like the other ones.
- PSP-2000: Brighter and less ghosting, but still not bright enough. Colours look washed out, too, like there's a huge gamma boost going on that can't be changed.
- PSP-3000: Brightest, least ghosting, Vivid colour mode fixes washed out visuals but has scanline issue on fast motion. I really noticed this on God Of War: Chains Of Olympus, it looked choppier to my eyes and not just because that game pushes the hardware to it's limit. Of all the PSPs though, this is the one I'd pick.
- PCH-1100/PCH-1000: Basically the two PS Vita Phat models are near identical, just the non-3G model is slightly lighter and you don't get that NO SIM message whenever you turn network features on so I like it better. OLED screen is beautiful, just about bright enough in most conditions and lovely vivid oversaturated colours, motion is smooth as butter. Premium build quality though I'd still keep it in a case because those screens are easy enough to scratch, crack and ruin. The bezel can give you hand cramp if you have small hands and been playing a couple of hours but hey, take it as a sign to have a quick break.
- PCH-2000: PS Vita Slim. Clearly a cost-cut version of the original and it shows. They've gone back to LCD screens, sure it goes brighter than the Phat does but like the difference between the PSP-1000 and PSP-2000 it looks washed out and has a crappy contrast ratio - tilt it slightly off-axis and watch the colours go all over the place. The blacks look very gray compared to the Phat. Little more comfortable to hold than the Phat but again, flimsy in comparison. As it's newer also harder to find on 3.18 or before firmware too.
So my WiFi only Phat Vita is still on 3.18 modded with TN-V for PSP games, TN-X for near-perfect PS1 games via Tekken 2 exploit and Rejuvenate for native SNES/Genesis emulators. Only drawback is for the latter - PSM Unity 1.05 doesn't allow you to use 444Mhz mode in homebrew that supports it, whereas PSM Unity 1.06 which works on later firmwares does. As I'm not really in the habit of trying to play
Star Fox at full speed it's a small price to pay to have the all-around best combination of features. I'd love a way to dump all my legally purchased PS Vita cartridge games to a bigger memory stick, I'm sure that'll come in time.
From the PS1 era I tend to play a lot of
THPS2 which has a lot of fast moving visuals of course, PS Vita makes it look great with it's clearer higher resolution screen rather than being scaled down to fit on the PSP screen (original PS1 NTSC games were often closer to 720x480 depending on screen mode, PSP is 480x272, Vita is 960x544).