I think the GTI/D looks better in 3 door.
VW's marketing people used a white 3 door for the launch ads and I'd say with good reason
https://www.youtube.com/watch?v=ufYZKfM37_4Just watching that makes me pine for my GTI
When I saw the first motorshow pics of the mk7 GTI the lines just looked good in the 3 door, with the car sitting lower and wider than a mk5/6 (both of which looked a bit blobby in 3 door form). The mk7 was given the same rear 3/4 window treatment as the mk1 and it just looked right.
Also the purist in me would say with reduced weight and flex the GTI *should* really be a 3 door in the classical sense.
The R however has deeper sills and I reckon looks better in 5 door format. It gives it a bit of 'length' to visually offset the very chunky bumpers and sills.
I'd agree with the post above saying the three door is good for visibility reasons with the longer side window but myself being a short arse which is the opposite to Bungleaio it means an awkward reach to the seat belt on the B pillar and the doors are too long for getting in and out of in tight spaces.
The mk7 has been around for about 4 years now (where did that time go, eh?) and still looks pretty fresh apart from the base models which look a bit dowdy.
You could argue the excessive number of windows on a 5 door make it look like a squashed Citroen Picasso and you could argue the three door looks a bit unfinished and that you should buy a Scirocco instead but neither will become design classics like a mk1.
So, three years ago I preferred the 3 door styling and three years later I kind of sway more to the 5 door.