In my opinion, there are three places on a plane that epoxy is absolutey mandatory. First is the firewall, second the landing gear plate and whatever reinforcements used for them, and tail feathers. What is used on the rest of the plane is pretty much just a personal preference, but those three places really need epoxy. A fourth would be joining wing halves and applying fiberglass tape around that joint, but other kinds of adhesive COULD be used here. I still use 30 minute epoxy. Just my opinion.