Almost no one care about how precise/reliable the keyboard pressing is, here, we built a damn cool equipment to examine this question. Broadly speaking, the time precision is good, mean variance is less than 0.2 ms.
Well, let me find the raw data first, since it’s been done for a long time.
Environment: MATLAB with Linux (Ubuntu 14.04)
Monitor: SONY Triniton at 120Hz
Keyboard: Mechanic number board