So I got my pap kiii plus in today, and lo-and-behold not only do the megadrive, master system, cps, neo-geo and game gear games run great, as everyone said, so do all the snes, gameboy and gameboy color games I tried. WITH PERFECT SOUND! Especially the snes is amazing! I tried donkey kong country, star ocean, toy story, super mario world and super mario RPG so far (all included with the device!) and all run 100% speed with no frameskip and 100% perfect sound, both in handheld mode and connected to my old CRT television (which is why I got this device, playing older consoles and watching old anime on the CRT screen as they were meant to).
I also put the english-patched tales of phantasia rom for snes on there as well, a game using multiple special techniques and chips, and surely enough the entire cd-quality opening song with vocals plays 100% perfectly and full speed! (and with the text perfect to boot!)
They must have changed the emulators, but boy is this awesome!
Oh and super mario brothers on NES actually works perfectly as well, at first in handheld mode I had strange sound (sped up) but when using on PAL CRT Television it sounds perfect! So it must be a PAL rom being forced to run faster then it wants, me thinks - but anyway, it can't be an emulator issue!
I did put tales of phantasia on there via micro sd card in my computer, not directly connecting the console to pc via mini-usb though, since seller where I bought it warned me that that might break the console by deleting important system files!
Battery is fine too, no issues, just works.
I am in heaven!
EDIT: in case someone "suddenly" wants to buy it from the same seller I got it from to be sure they get this version (box and everything is 100% the same) , here it is: https://nl.aliexpress.com/item/4-3-inch-Handheld-Video-Game-Console-build-in-1300-no-repeat-game-for-NEOGEO-CPS/32824646911.html?spm=a2g0s.9042311.0.0.b2704c4dsp2Xts
although it's ~43 euros there shipped instead of ~34 but at this quality that's still basically getting a freebie, so I can't recommend everyone highly enough to get it!!
I don't know if there is a difference in emulation quality but you never know with this Chinese devices, so I recommend everyone to get the exact same version I have, the 16 gb 3000 game white one =)