I haven't experienced any lag or issues with my RPi setup, and I'm using the original B. To me, my G27 feels the same with GIMX on the PS4 as it did with the PS3. One thing I have notice while reading up about using the RPi with GIMX is a lot of people start getting into extra circulars that will inevitably tie up the RPi's already minimal resources. I don't use anything other then GIMX with my RPi and I haven't had any issues. The only thing that I'm not sure about is if the GUI is running when I start start the RPi, which I hope not, but I've been running the image I've been using headless since I downloaded it, so I don't know. I've been taking the "if it ain't broke, don't fix it" approach.