Well, okay, but I'm certainly not an expert who knows the fine differences between all the models available on chat.com. So I'm somewhere between your definition of "layman" and your definition of "expert" (as are, I suspect, most people on this forum).

If you know the difference between 4.5 and 4o, it'll take you 20 minutes max to figure out the theoretical differences between the other models, which is not bad for a highly technical emerging field.