House4Hack GRBL laser controller

Logic level protection - keeps the laser disabled until all the safety interlocks are closed - preventing accidents
Redundant door switches (cheap chinese lasers does not even have one (;
Ability to use Pololu style stepper drivers OR big external drivers like TB6560 or Geckodrives: Allows the board to run both small 40w chinese machines and large cutters
USB support
100x100mm PCB - cheap to manufacture
Easy labeled wiring
Support for external Air/N2O control of two separate valves - allowing you to select which gas to pipe to to the laser head in software, depending on what material is being cut
Chiller support - keeps the laser off until the chiller is active to prevent premature failure of the Laser Tube