You're just proving scanesare's point there - you're focusing on just the advantages in pulling away from a standing start. When you say "my lady's GTI would struggle", I agree - yes it would, but only at pulling away and your R would be equally as bad at stopping or cornering (assuming an even/trailing throttle - if you're booting it, you shouldn't be out in those conditions).
You are wasting your breath. Lots of us have tried to explain this simple concept to CHB100. He is NEVER going to understand it. 
For me being able to have traction on a slippery slope and on the flat to gain momentum is the most IIMPORTANT FACT. While others with 2WD spin 240 horses without progress.
Once on the road I still feel more confident in The knowledge that I’m less likely to get stuck! Albeit similar both may be in gentle driving in icy conditions.
Friend I do have both to try in those conditions so is my true experience and not garnered from hearsay
Also you seem to think I am claiming something I am not to the point of boredom.
Please come and have a test in mine in such conditions in said situations or any come to that.
I won’t bother with rolleyes.
Dearie me you boys still don't get. So you don't think
To repeat to OP if you can afford all incurred costs buy an R over anything else.
Surely the most important thing is to have traction to lose momentum, not gain it?
The disadvantages of not gaining momentum are simply time - the disadvantages of not losing momentum could be time, money and lives.
As has been said - you're obviously blinkered in your opinion and not open to others viewpoints so I'll probably leave it there. I'm off to push a double decker bus up a 1 in 4 hill on my own - it's probably easier than having a reasoned discussion with you.
If you don't gain momentum pal you don't go anywhere until a 4WD tows you out!
So you are saying a 2WD is as good or bad as a R in ALL situations, if not you agree with me. Blimey I can't get it between your ears can i, I wonder why

Still one day for sure you will hopefully get the chance to find out. As you seem to ignore my own experiences with silly juvenile
comments.
Nope "pal", if you actually re-read it, you'll note that I actually agree that all things being equal, an R will pull away better than a GTI, even one with the PP. It's even quoted above in my post. What I'm also saying is that it's at this point that the advantages end - you'll have exactly the same braking and cornering abilities in the GTI as the R. Especially when you consider the only time an R is 4wd is when you've lost traction accelerating as it then starts to feed power to the rear wheels.
You seem to think that it's either black or white, either...
a) an R is better than a GTI in ALL situations,
or
b) a GTI is as good as an R in ALL situations.
Neither of which are true. It's been repeatedly said that an R will pull away better than a GTI - it even does it when there's a lot of grip, nature of the 4WD vs FWD beast. I'd also say that in any level of grip, the GTI PP will brake and pull up in the same (maybe slightly less, it is lighter and has exactly the same brakes, after all) distance as the R. Feel free to do some tests of your own as you have access to all the equipment.
As for my "silly juvenile" comment - maybe it comes from exasperation that some people won't accept a reasoned argument. My argument (and many others) is that we
AGREE WITH YOU that in any condition (especially slippery one's), the R will pull away better than a GTI. However it won't stop better, which (in my opinion) is probably more important. Anyone can have as much driving experience as they like, but it doesn't stop someone pulling out on you etc.
Here you go, a rolleyes just for you - saved you the bother!

Anyway - apologies to the OP for the off topic "bants" and back to the original question. I got a GTI PP as I needed a car sooner rather than later when I got it - had I been able to wait, I'd have got an R, especially as after I'd specced mine up, it cost the same as a vanilla R would have done.
In my opinion, the GTI definitely looks better (which is subjective) and once moving, drives better (albeit slower as it has less power) but it's plenty fast enough for me (especially with a tuning box).