Octopus, squid, and cuttlefish get a bum rap from a lot of folks, but that’s only because a lot of folks don’t know how to cook ‘em. They should never be tough like “rubber bands.” The rule to follow when cooking cephalopods is to cook them very, very quickly (grilling works well), or over a long time in a braising liquid. Anything in between will yield those rubber bands.
Their flavor is mild and sweet. The body of the squid is a perfect shape for stuffing, too.
Buy the freshest you can find; they should smell good, and as with buying any fish, their eyes should be clear.