If you're 42 and plan on staying driving distance from NYC, I say come to Delta. Upgrade will be quick, or you'll be able to hold WB FO eventually if that's your jam. WB captain might be out of reach, but you'll still have a good life. Other bases will never have the movement NYC has, but being in NYC I'd say it's worth leaving B6 for DL at your age. Other bases I'm not so sure.