Gregg, I think I see what you intended now, but the humour didn't come over in the OP (for me, anyway), which is always the hazard with humour.
Not sure if we were operating at cross-purposes with how many people read non-fiction/memoir stuff. Yes, I do know people that read non-fiction of many different sorts, and some that read memoirs, BUT those that do (that I know of) read it because the particular subject/experience is of relevance to them. I would normally imagine that the two different sorts of writing would be (at the start, at least) targetting two different audiences. There are examples to the contrary, but I think they're exceptions rather than rules.
I doubt if there is a rule that says memoir is commercially better than other non-fiction on the same subject, or vise versa. I suspect it has more to do with how effectively the author can handle the subject in either form, than the form itself. (There are some fiction stories, I find, that just have to be told in the first person, they wouldn't work any other way, while others would fail badly in the first person.) Find out what seems to work best for you and your subject, and give it a try.
Other than that, I'd just re-read jandrew's post, I think that says most of what you really need to know.
