As long as CC aren't screwing up the MM, I would say go with it. It is cheaper, and since you plan to run an external bec and a fan and capacitor it should work fine. I have 7 or 8 MMs and they all work great all the time on 4s. And they are cheap...best feature IMO.
$300 plus esc for 5s? It is small, and appears to work. I will stick to 4s and a MM. Cheaper, battery weight is lower, and repairs cost 50 bucks... Repair times on the other hand...