I finally switched from a basic framing hammer to a titanium one after my last deck job, and the difference in arm fatigue was huge. | Carpenters - Pinecone Attack
Used to think any hammer would work until I bent three nails on a single joist. Bought a framing hammer with a straight claw and a milled face, and it was like night and day. Now I keep the old one just for picture hangers.
Actually a basic claw hammer is fine for a lot of deck work. The real issue is using the wrong type of nails for the job. A smooth shank nail with a basic hammer is a bad time, you need those ring shank or screw shank nails.