electric choke

whats the difference between manual and electric choke on a carb, and which one do I want?

also does anyone have or know where to get calibration software for delphi/gm mefi 4 ecm?? I only know of 2 programs PCHud and InGenius Pro, any info would be good/

The electric choke works automatically. It controls the enrichment of the carb without any help from the driver.
A manual choke is just a knob you pull inside the car to close the choke when doing a cold start. Working them properly takes a bit of skill and experience or you can flood or stall it, if you open it too late, or too soon.
The electric choke is better, unless you have some sort of oddball race car, etc.