I have noticed a big difference in throttle response between a "cable-throttle" controlled vehicle and a "computer-throttle" controlled vehicle. Vehicles with a computer system activating the gas pedal seem to have somewhat of a lag when accelerating. It's only for a split second, but is noticeable.
A good example would be between my idi and 6.7 psd. If I stab the throttle on the idi, it is very responsive and rpms go up almost instantly. On the 6.7 psd, you stab the throttle in park, rpm's will go up, but not as rapidly and high. It's almost like the computer needs more time to process what just happened.
This is not a delay inherent to being computer controlled or drive by wire, computer controls are capable of being instantaneous. These driveability issues are forced on people by the EPA. Before the ridiculous delays with drive by wire it was absurd engine behavior when letting off the throttle either slightly or entirely. EFI engines seem to leave the IAC open to slowly come down to idle, and annoyingly when letting off the throttle to change gears the RPM actually increases. Compare that to a carbureted engine which has clean crisp immediate throttle response, or a mechanical diesel which does exactly what you tell it to and nothing more or less. The major driveability issues with EFI were a showstopper for me, let alone to added cost, complexity, and reliability issues. No EFI for me.