I'm surprised too that Sting Eze and After Bite use different ingredients. Sting Eze has benzocaine (an anesthetic) plus phenol, diphenhydramine hydrochloride, camphor, and other exotic chemicals. The benzocaine dulls the pain, the diphenhydramine HCL is an antihistamine to reduce the itch and swelling, and I think most of the other stuff in it is supposed to smell like it's really doing something! Anyway, based on the ingredient list, I should thing Sting Eze is fast and effective.
After Bite mostly has ammonia, which is meant to neutralize the bee venom. The After Bite people, of course, claim their approach is better and that products such as Sting Eze simply mask the pain. To which I say, so what's your point? I want the pain maskedperiod. Given After Bite's popularity, though, I'm pretty sure it must work well. (Although note that the pain of most bee stings diminishes rapidly so long as the stinger is pulled out.)
Anyway, I see only one way to answer your question: You need to head into the woods armed with both Sting Eze and After Bite. You MUST find some bees and annoy them. Then, all stings on your left side get the Sting Eze, all stings on the right After Bite. Before application, rate each sting for pain on a scale of one to ten (ten being "Oh s***t, that REALLY HURTS!"). Apply the products, then at one-minute intervals re-rate each sting's severity. E-mail the results of this test to me, and I will post them immediately on Outside Online. Think of the gratitude and admiration people will feel when they receive this empirical research.