I don't prefer any putty, I like to make parts fit correctly ;D
But if I do need it I just use ACC and file it down. I don't own putty, but back in my 1:25 car days I used the green stuff to do body work. A month later you can still make a dent in it with your fingernail. After that I only used 2 part puttys, the one I tried was milliput I think. It worked much better.