Hiya mate,
Welcome to the best forum in the world!
I would say it really depends on what the cars offer. I did pay extra for a low mileage gti when i got mine but this was only because i fell inlove with the car and the 1 previous owner had really looked after it.
Had i seen a car in equal condition with more miles i would have considered it all the same.
The VW engine is by my experience a tough creature! They have one at there HQ that has done a genuine 400,000 miles and still running!!! So mileage is not necessarily an issue if the car has been looked after and properly maintained.
Depending on how it has been driven and who as loved/hated it behind the wheel, most big things maintenance wise tend to need looking at between the 60-80k mark. For example, belts - mainly Cam, clutch, brakes, exhaust, bushes. etc... My point being a well loved GTI with 100k on the clock but relatively new brakes, clutch, exhaust, belts, bushes, can be a better bet than a thrashed GTI with 50k on the clock thats looking at a new belt, clutch, brakes, exhaust... you get the idea.
Tis a question of balance. My advice is to read the threads on this forum and familiarise yourself with the common issues and find a car that primarily you fall in love with and enjoy a good test drive in, then way up what may need to be done to it or what it has had done already. Mileage then is not so much of a problem.
I have seen GTI's with 150k on the clock running like brand new and GTI's with 40k on the clock running like one legged greyhounds!
Hope this helps you mate, either way you have made the decision to get a GTI, know you have done the right thing! Merry Xmas!
