I have the 4280. I don't own Guitar Hero but I play games on my Kuro. The fastest reaction game I have is GT5 Prologue at 1080p and so far it seems to be fine, I don't detect any lag. Lately, I'm also spending a lot of time on Mario Kart Wii which is 480p on the component input and there is no noticable lag either.
However, PS3/Wii are over a wireless bluetooth controller which has its own lag anyway! My friend is claiming the wireless PS3 controller lags and affected his timing on Everybody's Golf. I'll probably get my Tiger Woods PGA on the Wii to see. But so far, no problem and the 4280. No blur, no image retention, no delay, GT5 looks amazing as does Mario Kart. I may also add Devil May Cry 4 with lots of dark scene makes LCDs cry and the Kuro is so much better dealing with it.
BTW, I do wonder how people measure the 50ms delay...