So in essence to weigh up the lease/ buy deal you should weigh up the total cost of ownership.
I guess there's an element of capex (capital expenditure) and opex (operational expenditure) and working out what you are more comfortable as a monthly outlay. I'm no accountant but it seems to me that you may think you are only paying £300 per month on a car loan but when you factor in depreciation then you (on your average new car over 3 years) are paying something like £500. IF you intend to move the car in 3 years that is....you could always buy it, love it and keep it for ever...
Else pay £500 pm and get yourself a brand new Gti
but if you are like me, that's just too much to find each month out of my salary. But you can just walk away without the expense of a sale, hassle of time wasters etc
http://www.lingscars.com/Volkswagen/Golf_GTI/176420-2.0_TSI_16v_(207bhp)__Hatchback_3dr_1984cc-personal.html^^^ I haven't looked into the ins and outs of that one, just an illustration. I am sure there must be an easy calculator somewhere that works it out for you....but my theory is that there is not much in it either way.