I have one of the new Golf GTi mk5's with DSG gearbox.
I have found that the slightest touch on the brake pedal causes the computer to cut off fuel and so you have no control over the accelerator for a moment or two.
Major places where problem occurs:
Starting on an incline
Brake before corner then for a moment you are left with no power to negotiate the bend.
Brake before island, once again left with no power when you want it.
I consider this to be a safety hazard, twice now I have been stalled across a main road waiting for power to come in with traffic bearing down on me.
VW say this is normal - I wish I had not bought the damn car.
One more thing, combined petrol consumption in literature is 35mpg but the best you can get is 26mpg.
Don't buy a Golf GTi mk5 DSG until this sorted.