I read these posts and I would also like to have a Stop button feature, even if not on the GUI but available as Midi Binding. I just got Superlooper working last night and it's pretty good. In my situation, I have a piece with guitar synthesizers where I build a starting loop, develop solos atop of it, then I stop the loop and play other parts, and at the end the same loop is brought back from the beginning. As everydayjones stated, this is a standard feature in most looper pedals.
Many thanks for the great piece of software!