I'd say the 7.5 ECU is bang on, a lot off potential. As a stock system you have a Crankshaft sensor, knock sensors, MAF, MAP, Lambda and a potentiometer detecting TB angle, DBW... which all gives plenty off play for tuning.
Think the question should be what are you after from your golf?
I quite like the look off the megasquirts ecu, very diy, looks quit intrusting if you are building a kit car etc...