Computer Tuners which one?

Ok I want to get a tuner.
But which one?
I need opnions and pros and cons to each.
What do you like and not like about your tuner.
No B.S.
Here is what I want to do:
1. Improve the Auto trans shift. Less slush and more firm.
Also try to eliminate the confusion you can induce into the tranny shift if possible.
2. Performance of course HORSEPOWER.
3. Throttle response.
Those are the top 3.

Vehical:
2005 Stang GT of course.
No Mods other than a Air-Hog filter (Not a mod).
Info Info Info is what I want.