After you spend a few years in a truck, shifting all day, you appreciate an automatic more.
I like mine, but it needs some modifications.
They both have they're pro's and cons.
A properly calibrated automatic will beat a stick anyday.
dumping the clutch is also fun, and u just cant do that with a slushie... :'(
I'd stay away from the cheaper shift kits.
they can spike line pressure, and cause too much heat.
There is a mod you can do called the J-mod to firm up the shifts, that requires no parts.
you'd have to search for it.
For serious performance, Lentech is the only way to go.
I have they're valve body, and a staul on the way once i'm done with engine mods.