Quote Originally Posted by RogueJK View Post
I'm personally not a fan. In my experience, they're super-swingy, due to the fact Beholders don't have much HP but come with the plethora of save-or-suck/die eye rays, plus the random nature of which rays get triggered at a time. They seem to either hit one end of the spectrum or another: Anti-climactic cakewalks with good prep/good rolls, or frustrating near-TPKs with some bad rolls.
IMO they're best as a supporting monster adding chaos to a highlevel fight, rather than a main enemy. 5e beholders are very random and can get very hard countered (or even just shot to death pretty quickly. They are not tanky) so they're not great as a boss monster because its just too whacky and wild.

But if they're just there to be a supplement monster to a superpowered boss? The chaos is great for spicing things up.