I would agree with much of what has been said, but, nevertheless, I would definitely not buy one again and certainly not one that does not have a warranty - my Dieselgate warranty is going to be good until 2024. My '013 is my 4th VW TDI I have owned since 2002, all bought new, and the build quality especially in regards to the complex emission system, just is not good enough, at least for me.
My suggestion is to ponder the Consumer Reports frequency of repair data and their recommendations for used cars to avoid in the 2012-15 time frame before your decide to get into one. Yes, it gets amazing fuel economy, but a lot of other models, even gassers, are nearly as good and they are a far better long term ownership prospects, IMHO.
Some may suggest to delete the DPF, adblue etc. with a Rawtek exhaust system and put it a stage 2 chip, not sure of the costs but maybe in the ballpark of $ 2,000 if someone does the work for you. That may ameliorate some concerns at least as to emissions issues and boost mpg, but at least for me is totally not cost effective, as it would require driving the car for hundreds of thousands of miles and decades of ownership to pay for itself.
My other car is a 2005 Lexus LS430 I picked up to $ 10K 3 years ago at 109K miles and the improvement in build quality between the Lexus and the VW is totally night and day.