I remember my Mk5 GT TDi fondly. Suited my needs, and i'd have had no qualms having the Mk7 version if it weren't for the fact that by the time i'd added all the options I wanted it ended up being more expensive than the GTD.
That's the main issue with buying these new; a well specced version doesn't make a lot of sense compared to a GTD or a SEAT Leon. You need to find a used one that the previous owner loaded up to get good value. And those are not that common.