When I make a mistake with the ATG, I roll off the tape like rubber cement. If I have already stuck it to another piece of paper, unless I move REALLY FAST, it is not coming apart.
My pieces have fallen apart if I forget to press a bit.
THe gun itself has never felt too big or heavy.
I use the 1/4 tape. If I need 1/2, I can always add another row of tape to make it bigger, but I can't take 1/2 inch tape and use it on soemthing small.
I've been using the ATG for almosr 2 years now and I have not had to go back and re-do projects.