I use excluders more now than I did years ago. Here is why? Years ago, I was told about fantastic fall flows and all the honey you can harvest. So I would not use an excluder as the bees had all year to back fill the top and push the queen down. But now I leave the fall honey for the bees, which coming off a dearth in July and August, they need the feed anyways.
So what I do now is use the plastic type excluders.
I have a upper entrance (Not top entrance) on all my second hive bodies. By the time I am ready to super, the bees are using the upper entrance. It consists of a 3/4 inch hole. When I place the supers on with an excluder, I'll plug the hole in the brood chamber. Since my supers also have a hole as an additional entrance, the bees just naturally seek out the hole postioned 6 or 8 inches higher. So within seconds of putting on a excluder and supers, I have bees going in above the excluder.
Now some will say "But you will have pollen in your supers!" And that is why you turn the plastic excluder sideways, which allows the bees a 1 inch gap in the front and in the back to allow bees to pass unobstructed. The queen almost never goes all the way to the edge of the excluder to pass around.
So what you end up with is an upper entrance above the excluder, bees willing to work the super as soon as you put them on, a lessening of congestion in the brood chambers, increased ventilation, and NO brood in the supers at the end of June, when I normally like to take off honey.
July and August around here are dry dearth periods. So I take the honey off and make my summer splits and actuaclly will start to get them ready for winter in late June when the flow lessens. Going out and finding brood in half your supers does not allow you to control what you are doing. The bees will still bring in nectar, but I'll use any excess for feeding splits, etc. But those days of waiting till September for harvesting honey are long gone.
I don't buy into any negative comments about excluders. It comes down to managing them, and using the in the manner that allows for the desired results. Excluders are like any other equipment option. What's the use of SBB without the use of hygienic bees? Whats the use of excluders without making the bees react and use them as you require?