I really liked the idea of top entrances, it made so much sense, and maybe I thought it would solve all the world's problems. But.....
The advantages of top entrances if I remember them all:
Top ventilation with no mold, and with solid bottom, hive stays cooler.
Less problems with weeds, snow, and dead bees blocking entrance.
Less problems with mice and skunks.
Now that I've had the chance of using them, I didn't really mind as one described it, a tornado of bees when working them. As some have said, just standing there causes a bunch of bees flying around. But what bothers me is the bees going over the edge when you have more than one box. I smoke them out of the way but before I can get the box back on, they are all over it. The twisting movement only shears several heads. And what I thought would make the bees cooler and not hang on the outside didn't seem to work out. Curtains of bees hanging from the roof overhang, seeming to me blocking the ventilation I thought would keep them cooler. Who knows, maybe there'd be more outside if it was a bottom entrance. But my past hive didn't seem to have any more outside. And I thought they were to bring in water and cool the inside. Guess 90+ degrees is too much. What if you really needed to get in and work them? What do you do with a foot of bees hanging off the roof? Sometimes I see them still hanging there early in the morning. I thought they were a little cramped for room and added the second box, but now it's turned hot again, there are still a lot of bees hanging outside. I guess I could not let the roof overhang, but thought that would prevent rain coming in.
Unless someone can tell me how to deal with this or suggest an alternative (middle entrance solve anything?), I'm considering using bottom entrances. But maybe going to top entrance for winter.
What I would be swapping by not having top entrances during the summer portion:
Weed problem at the entrance.
Maybe harder for them to evaporate the honey.
Skunk problem. But if the bees are on the outside, it's just a matter of slurping them up anyway.