I have never driven a GTI before 
But i think i would prefer manual rather than DSG....
Car just feels more lively.... (But bare in mind I'm comparing this to the Tiptronic/automatic gearbox in our Pajero)
Ah, but the DSG is a quantum leap away from any other kind of conventional autobox (epicyclic gears and a torque converter), even if they do have "tiptronic" controls.
Before I ordered my current RS4, I drove the latest S6, which dispite having the tweaked Lambo 5.2 V10 - still has the conventional autobox with tiptronic. The box was truely aweful, and I really cant see why peeps buy them (the autoboxes).
I've driven many, many different autoboxes (and CVTs, EasyTronics, and even bus pre-selectors

), and even some of the very best ones, like BMW autos - really are no comparison to the DSG.
I really would recommend trying the DSG, ideally for a whole day, before dissing it.