All I have used has been the 5 and 30 min. epoxies from Boss. I have found that you can easily pick these up at your local hobby shop or even Hobby Lobby as well.
As you can see, the differences of opinions on the handle epoxies is as varied as opinions on anything else. This could easily become a heated debate among some, but I believe that everyone will agree that any of the mentioned products will be suitable though one could possibly be better than others.
I can't tell you which is the best, only that the one I use works and is reasonably priced with fairly easy clean up. I haven't used it on a "hidden pin" piece, but I know several makers and at least one Master Smith who use the same stuff.