[Xperia Play Themes and Apps] LordBattleBeard:
Ok, so here goes...

FPse

I use PSXperia where possible because you just can't beat its speed and glitchlessness (probably not a real word but I dont care) compared to any of the unofficial emus. Where a game just won't run on PSXperia, I will use FPse. Most of the time it works but the UI is unintuitive and I find that the updates don't go through any proper testing; as they usually break more than they fix. The developer also has the communication skills you would expect of an angered autistic person.

N64oid

I tried the free alternative to this which has touchpad support for the Xperia PLAY, but overall I found that N64oid trumps it on compatibility and speed, which is more important to me than using the touchpads. Its a shame the developer halted all development on this now, but in spite of this, it still remains the best emulator for n64.

My Boy!

I have a very big GBA games collection so finding a decent emulator was important. As such, I tested practically every one I could find on (and not on) the market. The core of this emulator is definitely the best. Why? I can play practically any game with frameskip disabled and not get any lag whatsoever. I haven't encountered any saving issues, cheats work perfectly and it supports features no other emulator does (Gyroscope/tilt/solar sensor and rumble emulation). Before this, GameBoid was the best but all development on that stopped a while ago now and My Boy definitely took its crown long since. As for GBA.emu, I expected it to be the best before I had even installed it. I was bitterly disappointed. The core is poor to say the least, it lags every few seconds even when frame-skip is disabled. It has a nice minimal UI but that doesn't make up for its shortcomings. It feels like it was rushed to release and still needs much development to put it on par with even GameBoid. I will give a brief mention to VGBA, in one word: DRM.

GBC.emu

Most GBC emulators are now on par in terms of emulation speed as most of them are based off the same freely accessible source. GBCoid, JohnGBC, and others, get the job done. But I think GBC.emu is in a league of its own because of features the others lack. It lets you disable linear filtering if you like and has other filters to use too. It has semi-cheat support (doesn't support all ranges). And a feature that I think is great is allowing you to choose a colour pallet for standard GB (not colour) games, so instead of having a grey or green pallet for all older games, you can inject some alternate colour into them.

MD.emu

Plays all the games I throw at it with no lag whatsoever. With the same ability as GBC.emu in disabling linear/other filtering if you like. Development is ongoing (most others appear stagnant) which bring new features to it. Like more recently, Mega CD support, which although patchy, its getting there. And like all this developers emulators, is Xperia PLAY optimised which gets extra credit in my book.

Snes9x EX+

Back on the market after being removed and still FREE. Plays every game I throw at it no problem. The same feature-rich options and benefits of this developers other emulators (as mentioned above).

NES.emu

The same feature-rich options and benefits of this developers other emulators (as mentioned above).

NGP.emu

Ok, I'm going to throw this out there straight away.. this emulator is desperately overpriced. But if like me you want to play the small collection of obscure games (remember Sonic the hedgehog: Pocket Adventure?) that were released for the NeoGeo Pocket (Color) all those years ago, go for it.. this emulator supports them all perfectly.

PCE.emu

PC Engine/TurboGrafx-16 emulator. Played all the games I've thrown at it. No lag or other things of mention. This emulator beats similar emulators purely because of all the little features it has and the developer is always updating it to make it better. Also like all his other emulators, is tested on an Xperia PLAY.