Evo što je jedan pametan čovjek napisao o famoznom input lagu:
The point is that 3 frames lag, 50 ms, is VERY little, almost negligible, it can be noticeable only in some situations in first person shooters. It's absolutely impossible to see such lag on the desktop, typical human reaction on simple events (there's generally accepted therm for this type of reaction in russian but I don't know for sure how it's called in english: time between simple event like flash of light and muscle contraction) is about 200...250 ms, 4...5 times larger than monitor's lag, so 50 ms is really a very little.
In most cases when users believe they see this lag it's just an ordinary auto-suggestion: first they saw thread in forum, read that their monitor has a lag than believe that they really see that lag. Many users switch to LCD from their old CRT monitor, but when you do this, almost all changes: screen size, resolution, response time, even brightness and contrast... Many people don't like simple explanations like "you've just changed your desktop from 1024x768 on 17" CRT to 1680x1050 on 21" LCD, now adjust your mouse speed and acceleration!", they want more complex, scientific-like explanations. I've seen a lot of forum threads with discussions about lag, backlight flicker due to PWM control, matrix flicker due to AC current (liquid crystals degrade when they supplied with DC current, so all LCD panels use AC inside), even about CCFL spectrum and polarization of emitted light! Almost all of them are just attempts to find overcomplicated explanation of simple things.
So I don't think 3 frames lag is a real problem. It can be really seen only in some rare cases. Moreover, even in first-person shooters if someone got used to monitor with lag he will find himself uncomfortable on monitor without lag, because adaptation to specific monitor matters more than this monitor's parameters, that's how our brains work. I don't want to say that monitor's parameters means nothing -- but usually less than most people think.