I'm going to go the other way. I've never used gorilla glue. But I have used epoxy on plastic. I don't see it being an issue of strength as much as not flexible enough. Or perhaps it's the oily base of plastic that over time bleeds to the surface before it dries out. Something like Pliobond works fairly well in plastic/metal bonds. It's not as strong as epoxy, but it won't pop off either.
First of all, epoxy comes in a huge variety of formulations. If you go down the 3M catalog you'll see that they have one that is hard enough to sand and drill holes in and they have a "super flexible" one, and they have products in between. McMaster sells 15 different 3M epoxies (and 11 other two part adhesives that look like epoxy but are actually something else.)
But that may not be the issue. Plastic is very tricky. Not all plastics are the same. If you want to bond a hard plastic, you may have good luck with a randomly chosen epoxy with good surface preparation (e.g. roughing up the surfaces). But if you want to bond a soft, slick plastic such as polyethylene then these epoxies won't work well. In fact, very few things will bond polyethylene well. For bonding acrylic, regular epoxy is also mediocre.
For bonding general slick plastics ("low surface energy plastics") 3M makes DP-8005 and DP-8010 which work very well. They are kind of expensive and 3M does not recommend hand mixing, so you have to get the gun and use static mixing nozzles (10-1 mixing ratio). But they really work. I bonded zinc plated magnets to polyethylene with this stuff about 6 years ago and have been putting them through the dishwasher on a weekly basis without any failures. I use a sheet of teflon (PTFE) as a backer for epoxy work and regular epoxy pops right off. The 3M adhesive stuck to the teflon so well that I couldn't get it off.
For bonding acrylic, you can use Weld-On #3 or #4 which basically dissolve the acrylic and melts the two surfaces together. (This is how you make an acquarium.) But the point is that if you want to bond plastic well you need to know what kind of plastic it is and seek an adhesive suitable for that particular plastic.
If you're concerned about bond strength, then at least 3M (and I assume other manufacturers too) publish spec sheets with advertised bond strengths for different materials. As it happens, DP-460 was the product recommended to me to bond brass to wood. But I usually use epoxy for things that requires a fast set and I don't generally have any problems with bond strength.
I have gotten the impression that in general, epoxies that bond more difficult materials or have other superior properties are slower curing, but I wouldn't try to generalize too far. I compared DP-100 Plus (4 minute open) to DP-460 (60 minute open). For DP-100 Plus the sheer strength in PSI for etched aluminum=3500, sanded aluminum=1800, ABS plastic=450, PVC plastic=250. For slower curing DP-640, etched aluminum=4500, sanded aluminum=3500, ABS=300, PVC=500. Note also that DP-460NS has sanded aluminum=2650. In fact, the non-sag version was significantly weaker on several materials.
The observation is that if you're gluing aluminum, most likely the DP-100 Plus is adequate, but it is weaker. Note that for plastic, the DP-100 plus is actually stronger on ABS than the one with the longer open time. Surface preparation can make a significant difference. (Compare etched aluminum to sanded aluminum. You're better off etching your aluminum and using the fast product than sanding and using the slow product.) In the end, if you really care about bond strength, you should check the manufacturer specs for the material you want to glue rather than trying to infer it from working time. The DP-8005 that I used to glue to plastic has a 3 minute working time and bonds PVC with sheer strength of 2050 and ABS with 1575, much better than the DP-460.
