Most noticeable change on my car was the throttle mapping. I went between oem and shark a couple times. Oem was clearly more "touchy" and the shark was more "numb". On initial change, I would rather the sporty oem, but the sharks really is better for throttle modulation at cruising speed.
Also, when letting off the throttle in 2nd and 3rd gear, the shark is much "smoother" to let off the gas and begin engine braking. With the oem maps the little jerk was very noticeable to passengers, now its nearly transparent if not completely.
De gustibus non est disputandum.