As Joseph Campbell said: "follow your bliss".

I agree with the comments to find a rate that will allow you to transfer to the civilian sector and to stay away from the deck hand type jobs unless you enjoy 20 hour days, always on watch, chipping rust, painting, polishing brass and general ship husbandry. The Boatswains Mates do learn how to tie cool knots and blow the most annoying whistle in the world but again, follow your bliss.
A guy I knew in boot camp joined to be a Quarter Master (QM) so he could learn to pilot ships. He was going to do his 4, get out and become a harbor pilot. Two guys I served with were BM's and are still in doing the same thing.
My first couple choices didn't work out and I ended up being a Radioman, I think they are called IT now but it gave me a clearance and basic training in Communications systems. Got my first job when I got out based on the clearance and basic skill set but again, do what you want to do and what interests you.

IMO the two choices you listed are quite different. Both have potential in the civilian sector. Which one will you be happy doing for the next 30 years?

Another thing to consider is the deployment cycle. When I was in the different rates had different rotations so might want to check that out. If you a hospital tech in a specialized area you may only go to large bases with big hospitals or as a CB you may deploy to BFE with a rifle to build an ice cream parlor while getting mortared.