Some reviews from people who own the monitor can be found here:http://www.overclock.net/t/1566153/benq ... wners-club
And Hexus has a nice review for this monitor now:http://hexus.net/tech/reviews/monitors/ ... nq-xr3501/
They mention a 22.3 ms value for input latency. So I had another look at this with the Leo Bodnar tester, and found settings for AMA (Advanced Motion Accelerator, or BENQ's name for overdrive) in the OSD menu. In mode "Gamer1" (which is recommended for racing games by BENQ) AMA is normally set to "high". However, you have 3 options available: off, high, premium. Switching it off causes significant motionblur so I would not recommend that. I don't see much/any difference between "high" and "premium", except the input latency (I did the Leo Bodnar measurements more carefully this time).
Port used: HDMI1
AMA Off: 20.0, 23.7, 26.7ms
AMA High: 19.7, 23.4, 26.5ms
AMA Premium: 19.1, 22.8, 26.0ms
So on average I would say the input latency is approximately 23ms. I don't know how Hexus managed to get to 22.3ms, maybe some difference in other settings. But let's be honest, it doesn't matter that much.