That's about the size of it Scott--some folks like one, some like the other, but when you get right down to it either one will do the job, and if properly made will do it well, with little difference between the two. Olympic shooters like endless, the fastest bow Norb Mullaney has tested was shot with flemish.
I do think it's easier to get a more consistent endless string from one maker to the next, as most flemish string makers have their own style that will vary a little from one maker to the next.
Jrchambers, you can pad out the loops on endless strings if wanted/needed (I've done a few lately).
Chad