Vinegar does a pretty good job cleaning up epoxy that hasn't set yet. I would take care not to get any in epoxy that is actually going to be sticking something together, though.
It's hard to know what "extensively" means.
I've used Raka, which I thought was pretty good. I add wood flour, fumed silica, or cotton flox if I want to thicken it, micro-balloons if I want to lighten it. Used straight, it wets out fiberglass pretty well, and the results seem durable. This is Raka I bought many years back, but looking at the site, I think they are still selling the same designations. There was a slow hardener and a fast one. For ordinary conditions, you'd use a little of each. I built a boat with it, and completed boats two other people had started. It does blush under certain conditions, but that's easy to wash off. If you are working indoors and it isn't humid, you probably won't see that. Recently, I used it on a board I'm going to use to replace one that rotted out on a garage door. Also, for making RNXish fuel pellets for a Jetex motor. Also some with sugar too. For that, I wish it was as thin as water. I think Raka may be similar to West.
Apparently, judging by the almost empty cans,
I worked for a week helping a guy build vacuum bagged boats. He would order his own epoxy chemicals. I have some of his epoxy, but I don't think I remember what the components are. I think the mix was 5:1 or thereabouts. It's pretty good for laminating, but makes lousy glue.
Apparently, judging by the almost empty cans, I've used up almost a quart of EZ Lam over many years. I can't remember enough projects to have used that much, but I guess I did. Works fine for laminating, can't remember if I glued anything with it. Just made a Jetex fuel pellet with it, too. I don't know if their formulation is the same as it used to be. At a minimum, they now have fast and slow versions. I also don't know if I believe their current claims about strength. Anyway, the stuff I had seemed pretty good. From ACP composites. The fuel pellet was the first time I've used it in years, but I can report that it's hardened up quite nicely in less than 24 hours, even though it's only about 20 percent of the weight of the pellet. Haven't burned it yet, but that's a whole other application than laminating or gluing.
I have a bunch of old hobby epoxy of various brands. Generally, the hardener eventually gets thick and skins over and turns yellow. I can often bring resin back by heating until the crystals re-dissolve, but I don't know how to bring back the hardener. They all worked ok. I've found that 5 minute epoxy is usually not terribly strong, and can be terrible with fiberglass, but I'm not sure that's true for all of them. I have a favorable impression of Devcon 2-ton. I've used up some JB Weld, but I can't remember on what. Sig used to have a 2:1 mix slow epoxy glue that set up harder than most. Hard enough to work well with fiberglass if you were stubborn enough to fully wet out fabric with something so viscous. Not sure how it worked as glue. Maybe just fine, I don't really remember.
I've had most of these long enough that I had to de-crystallize the resin at least once, usually by leaving in a car on a sunny, warm day for a couple of hours.
I'm going to answer the survey with 3, though if the hobby epoxies were all re-badged versions of the same thing, it should be 4.