Hold up, if QMK has been ported to ps2avrgb boards, isn't this an $18 "upgrade" to limit yourself to QMK only? The standard, cheaper PCB would have the option to use bootmapperclient or QMK. What am I missing?
Also what thought. Can someone help explain the differences between the two pcbs ?
The ps2avrGB PCBs are reliant on V-USB for their USB compatibility since the atmega 32a does not support native USB.
The QMK PCB here uses an atmega32u4 which does have native USB compatibility.
I had a ps2avrGB based board with a 32a in the past and it had more input delay than my TMK/QMK/o2d ones which all use either a 32u2 or a 32u4. It is not very noticeable for normal use and not even for most of gaming use, all your mainstream games (LoL, DotA, CSGO, Overwatch, Battlefield, etc.) will work fine, it's just that there cases where this affects you a lot like in rhythm games or high-level tetris or stuff like that.
In my experience ps2avrGB with a 32a had more input delay than Leeku's L3 firmware with a 32a, which had more input delay than all the 32u2/32u4 implementations I tried. I cannot predict how efficient the code that implements V-USB into QMK is, but I still believe that even the best V-USB implementation is slower than the native USB of the 32u2/32u4. But up until now all my testing was done with just "feeling it" and the hit-error bar in osu! , so nothing really concrete yet. I also did some other test where I hit a key which played a sound which was recorded with a microphone and I the went through the recordings and wrote down the delay(to compare the difference between boards, not to measure the base delay of each board, that wouldn't work that way), but other than confirming my speculations it didn't do too much as there was still too much variance in the single measurements to get a exact number in ms, I took averages of 10 though.
Oh also I don't think that V-USB supports N-Key rollover, iirc it is not able to use USB fullspeed which is necessary for N-Key rollover.