I've made 3 supers off of this colony in addition to being my starter and finisher colony. They are working on their 4th. The queen has space to lay in only 2 med boxes. Does having the entrance in the middle do better than top or bottom... I've seen no discernable difference.
I tried some with only top entrances but dislike having clouds of bees trying to find their entrances right where I'm trying to work. I personally feel it is more disruptive to the colony.
I have both. You can see the top entrances I use on my migratory covers in the link in my signature. Then I have a regular bottom entrance. I have yet to see a hive that prefers the top entrance during the warm season. Obviously in the winter when they are at the top they will use that one first. Otherwise I mostly just see bees fanning at the top entrance.