Auto Express did a road test and compared the 2. They prefered the styling of the TT but said the BMW engine was amazing. Not sure they were that keen on BMW styling but I think it looks good. I think they should have compared it to the BMW Z4 and not the 1 coupe to be honest.
Wierdly though they were both the same price - £26,350
The TT is nice but I found the driving position not as good and like the bit more space you get in the BMW, Audi servicing tends to be more expensive. However, the Audi is probably better made and you do see less Audi's on the road than BMWs
I don't think you are the 1st to be in this position though.