The key to cooking squid is either cook it very fast...or very very slow. Anything in between is rubbery, but not the kind of rubber squid I collect.
I dunno. I like small succulent squid for eating, although I'd like to try the Humboldt squid (big but not giant) that the West Coast had a run on a year or so ago.
Cuttlefish is good eatin', too. And octopus. I guess I just like tenticles.
Vampyroteuthis infernalis, is probably my favorite non rubber, non dinner type squid -- "vampire squid from hell," -- it has the largest eyes of any animal.