There's really not much difference, but I do like how the rub strips are more prominent on the Rabbit front end.
Personally, this call I'm going to say keep the stock front end..
Normally I would say do the swap because it's awesome to have something unique noone sees, but there's really not enough difference to go through the trouble. I didn't even notice the Rabbit and GTI front ends were different until you pointed them out in this thread. I just figured the Rabbit was a lower basemodel of the GTI..