i would say that driads would be better choice, but evil beholders not bad also

But if you dont kite maps you get no dryads in the early game, and they have 1 empty round before the reactivation of the skill.

You can call Dryads with 'Call of the Wind', so that isn't completely true. Also, phantom drayds to keep an enemy under indefinitely... and it works in infinite numbers of stacks of low level units. Beholders are only better when you have a single, or maybe two stacks of level 1 or 2 units.