I got My XD Plus yesterday from GPDs official site.
https://www.gpdxd.com/product/gpd-xd-plus-gamepad-black-32g/ I hope they do release a refresh rate fix for the plus. I noticed the SNES emulation was a bit off in Snes9X, I tried ePSXe and it ran great. I also ran NES emulation in RetroArch and it seemed decent. I still need to test GBA emulation.
Installed PubG Mobile and it ran smoother than on the old XD but the medium graphic settings breaks the game and you cant load it.
Doom GZ with the Brutal Doom mod (v21) is also running really well with less frame hitches and more options/features turned on. PPSSPP is better with Vulkan and more games are playable (Monster Hunter 3, Valkyria Chronicles 3).
The adoptable SD storage and ability to use the USB port for mounting the system to a PC for file transfer is great.
I use it with Caustic 3 for music stuff and the Nougat systems audio latency is good enough to use with MIDI keyboards and drum controllers.
I plan on rooting it, de-bloating the apps, and hooking it up to a TV and GameStreaming with Moonlight and a Xbox controller tonight.
One thing I need to do is see if Magisk can hide root from PS Vue to start the app.
Build quality is solid on mine. The buttons seem better but I had a pretty early version on the original XD. My old one had PS Vita style sticks the XD plus has a more grippy almost DualShock3 style domed textured stick. The hinge also locks into 2 separate places more like a 3DS where my older XD did not. buttons are higher and the D-pad seems better than on my old XD. Haven't dropped any WiFi connections but still need to test BT. Screen has less light bleed than the older one too.
So far I'm really loving the system.