i don't use them. it's one more thing i don't have to mess with. if you were doing cut comb or something like that, you might want to consider them. otherwise, why bother. some brood in the honey comb is no big deal and most of the time it doesn't happen anyway.
IF you use them, come back and talk to us first. there are some important things to do, or not do, to use them with any success.