I just received the device (grey). So far I love it! Feels great in my hands. It's my favorite since the CAANOO. Nothing has really satisfied since then for me. CAANOO had it's issues, but it still looked phenomenal and felt great to play. GKD350H has an incredible screen. Extremely bright at max setting. Very colorful. Great viewing angles. It's true 320x240. People say the LDK's are 320x240, but that is definitely not the native resolution of the display. the GKD350H also has a great d-pad in it's operation and placement. So for the best d-pad I've tried on one of these Chinese handhelds.
I've noticed issues with the GKD350H though that are disappointing. As someone else stated already; I was confused when the GBA and SNES emulators appear to slow down to 30 fps even though the FPS within the emulators are still at max. I hope this issue gets fixed. I'll have to try gameblabla's OPKs. I also notice when navigating through OpenDingux, it will momentarily freeze for maybe 2 - 3 seconds. My button presses are still queued up and each press executes quickly when it unfreezes.
I'm impressed by CPS3 emulation with the "fixed" FBA opk. Setting to CPU to level 7 it can run at full speed. For me, I love IGS PGM arcade games too. It seems the "fixed" FBA opk actually runs those games a little worse. The built-in FBA runs Demon Front at near full speed, which is still pretty awesome. Unfortunately, another PGM game, Spectral Vs. Generation, is around 30-50 fps in both FBAs.