Which PCB Gerber viewer to use?

PCB Gerber File is generated from the pcb design and it is an open format which defines the pcb manufacturing details.

After generating Gerber of the PCB design, it is recommended to check the gerber file using a stand alone Gerber viewer to see if there are any issues in the Gerber files.

But, the question is which tool to use?

pcb gerber
Example of a Gerber file

Various Gerber tools available in the market are listed below (I have used GC Preview or Gerb Tool in the past)