Well as for choosing one over the other it depends on how you cover and how well you know your material. If you've always used monokote, you know to keep a hot iron.
If you've always used ultrakote, you know to keep a cool iron, and then to shrink nearby covering first, then warm up your iron a little at a time and work out the wrinkles on curves. Sure it takes time, but it turns out just as good if you know what your doing. Another trick to ucote is to apply it as tightly as possible before even needing a heat gun, this will keep slack out of it to begin with. Then when you do heat gun it (give it a b-job as I call it) put damp rags on the seams, turn your gun on max and blow away. The rags will keep the seams from pulling, and the max heat will help to keep it from saggin once done.
I've gotten the hang of both and neither is really better. Its just what you're used to. The thing I do like about Ucote is that the color selection is huge, giving you an extra edge to creating a truly unique color scheme.

Dean, I've used the glue tecnique too, but have you ever used balsarite?!? Talk about a slick finish it blows glue and water away! (That is if you touch it slightly with 220 wet or dry) The stuff turns wood to glass, it's fuelproof, it won't warp any wood whatsoever, and it's dries as a plastic film itself, so covering sticks much better.

Give it a try!!!