It totally depends on type of driving that you do. For me the TDI fits the bill absolutely perfectly. I drive about 600 miles per week on medium / fast A roads, and to do this on one tank of fuel is very convenient. The way the Golf drives makes every journey a pleasure and encourages little detours now and again just to throw it around a bit. I haven't driven a GTI but as I need the economy then the choice for me would be (and has been)a TDI with a few choice extras to make long journeys easier. For me the difficult decision will be justifying not trading up to the new GTI diesel which will surely come along sometime soon. All the best with your purchase.