[Mack g17]

What is the better between the glock 19 And the 19C

[robocop10mm]

The "C" is for compensated. It has ports in the barrel/slide to direct some of the gasses upward. IMHO the 9mm does not have sufficient recoil to be of concern. The 9mm does not have sufficient volume of gas to make a real difference. Probably the only Glock that would truly benefit from the ports is the 10mm's.

[okdonk]

For protection i suggest the 19. For competition go with the "C".
Why? Speaking of protection, if you are getting out of your car on an empty parking lot at night, then someone at sudden coming to you intending to rob with a knife. You can easily pull out your gun from hip holster and shoot him with it without gas bursting out to your face. When aiming also, you wont get sight blinded as the gas bursting from the ported barrles will be visible at night.
Just my 2c.