I think the GTD reviews have been positive. if your disappointed with what you've read then the GTD is not for you.
It really depends on what you want your car to do.
Everyones requirements are different and it depends what you want your car to do for you.
for me neither the GTI or GTD are going to excite me. I sold my seriously tuned ED30 and bought a Nissan GTR back in 2009 in the quest for more power. and yes it was a rocket ship but I never got a sense of excitement or adrenaline I get from riding a motorbike. The build quality was pretty nasty and the running costs where shocking. I got rid after only 7 months and bought a new Triumph Speed Triple and a Golf GTD and have never been happier. I just don't get the feeling of being at one with the machine with any car as I do on a fast motorbike.
I'm just after a new car that appeals to me that can do big miles in as much comfort as possible.
it needs to look the part, have a quality interior and have a bit of get up and go and not cost the earth to run. The MK6 GTD I own now does all of those things. The new one is lighter, faster, better equipped and costs less to run.
I myself did way up the cost of the GTI v GTD as my daily transport and for me the GTI works out approx. £160 more a month due to lower running costs and better future value for the GTD.
for me thats £160 a month I would rather spend towards my new purchase. A New BMW 1000 HP4 Cant wait

If your toying with a basic spec GTD v GTI as your do it all motor and your not doing more than 10k miles a year and you want the best all rounder on the market today I would go for a basic spec GTI if the piggy bank allows.