We use them here and if the hive is strong and active they don't hamper the bees. Of course we install them on the second super on the hive.
The main benefits we've seen from using them is the honey is cleaner as in fewer bee parts are present, the flavor of the honey is better due to the combs not being used to raise brood.
Our bees tend to fill the bottom supers first then work on the upper ones.
