Just to toss a few cats among the pigeons (not catamarans - I've no experience there):
As well as the conditions, as most have said: A lot depends on the boat.
Even on a big boat, provided it's set up with a good strong centreline kicker
and powerful siderail vang preventers back to spare winches, it's often easier to gybe than tack, even shorthanded in a stiff breeze, if you're well practiced.
With a decent boombrake, properly set up, it's more attractive still: you can often dispense with winching in the boom, provided there's no chance of the mainsheet falls looping over something (like the binnacle!) and maybe wrenching it.
Another variable is how well the boat 'stays'.
If it's prone to missing stays (failing
to fall off onto the new tack) in big seas and strong winds, it may be preferable or even necessary to do a chicken tack, which means gybing.
It can be a test of character having to make this call if you've limited searoom down to leeward, say trying to sail out of an untenable anchorage - but that deviates from the OP's question: he was talking about going from a beam reach to a beam reach....
But now that I've raised it: sailing ships used to have to gybe rather than tack in stronger winds (or if poorly designed or fouled underneath): they called it 'wearing'.
(Not a fair comparison, though, with 'fore and aft' modern rigs: squareriggers were very safe and easy to gybe by comparison, and it could certainly be done much more easily than tacking them, which was seriously tricky)