This is a very hard question, but I will try to steer away from the horsepower vs torque debate...very good opinions differ and I get brain freeze just thinking about it.
The real-world experince will differ from individual to individual and I feel you have to drive both to get a feel for yourself.
The DSG will take alot out from the "experience". But assuming a normal cruise without WOT(wide open trottle), With the specs you gave above, the only difference will be the petrol accelerating a little better in town, while the diesel accelerating better on the highway(lane change to scoot past a truck without florring the gas pedal).
That^^^ and the noise of a diesel are the only experience. I personally think a gas engine sounds better and will put a smile on your face each time you hit WOT.
With the DSG being too similar for me, lets throw in a 6-speed. From driving without WOT (just a civilized commute). I find VWs with Gas equipped engine better for stop-an-go traffic while the the diesel gets better when you are past third gear because you can ride wave of torque and not have to change gear often...the faster you go. Probably has to do more with gearing though as similar cars with different engines are always geared differently.
Going deeper, I would not say the USA TDI is alot cheaper to run,
Diesel is not as cheap as it used to be a few years ago. Diesel is only 8c/liter cheaper here. China and India growing indistilization is currently driving the cost up, so even though the TDI gets better milage, but could still take about 5 years to make it back. If you plan to keep it longer than 5years, it starts to save you more money as the engine can easily run up to 200k without issues compare with what you will be faced with on a gas engine.
- compared to the 2.5, I'll take the 2.5 for cost.
- compared to the GTI, I'll take the GTI for looks.
Cheapest Golf to rack up miles on will be the base 2.5.
Golf with more options, better performance(than 2.5) and better mileage will be a TDI(but it is too close to the GTI's pricetag)
For just Performance and looks, then the GTI.
Also, I will substitute your USA TDI for a GTD
GTD: 2.0L turbocharged diesel - 170 HP and 258 lb-ft of torque
GTI: 2.0L turbocharged gas - ~210 HP and 207 lb-ft of torque
The GTD has
- cleaner emmissions (for tree huggers who want to feel they are saving the planet)
- more torque
- more fuel efficient
- Quieter diesel rumble (compared to the 80s and 90s)
The GTI has
- petrol,
- better acceleration from stop.
- sounds better.
- Nice rev range.
- Faster than the GTD on a track or when using WOT.
So...if we get the Euro GTD here (Engine, bumper and seats) about $2000 more than the GTI like it is in Europe(~900euros), then my order would have been for a GTD instead of a GTI. But is will still be a tough sell for VW.