I never had a problem with my mustang that I could attribute to EFI. I thought I would have EFI issues, but it turned out to be a burned plug wire that would cause some weird driveability issues.

My EFI mustang never left me stranded, except for a bad battery and it was late at work so I had nobody to help push start it. It had 140k miles on it and still ran 13's with a heavy stereo in the back and the A/C blowing cold. Fox cars are probably the best daily driver fun car on the roads.