All of this is probably well known to most ppl here but is new to me.
In making my two Mini-Cups, I have experimented with various glues. I
just cannot resist the temptation to do somethign a different way.
So, here is my opinion.

Gorilla Glue: fairly easy to use requiring no mixing. It has less
strength than epoxy and as been stated by others, no ability to bridge
gaps with any holding ability. It really needs a tight fit.

West Epoxy: Convenient with the little pumps for mixing, holds really
well and bridges gaps. Very expensive and no matter how much of the
colloidal thickener I use, it sags and starts to run before it sets.

MarineTex: Another epoxy formulation I think. This stuff I like most
of all because it bridges gaps, holds like hell and does not run.
Very expensive.

Bondo: As reccomended by the Mini-Cup plans. Seems to have little
strength and I wouldnt rely on it as a glue. It does fill gaps really
well (no strength though) without running. It sets VERY fast. Fairly
cheap.

Conventional Fibreglas resin (the stuff that stinks): Not too bad to
work with, not sure of its abilities as a glue, havent tried it as a
filler, reasonably inexpensive