Being deployed right now, the only visible difference in service branches that I see is that we eat at different tables in the dining facility & have different colored PT gear.
But really, if you want to learn about the differences in services & specific jobs, have a specific job or skill in mind (something you are interested in) before you visit a recruiter. Nothing against recruiters, but its their job is to fill positions where they need recruits, so thats their angle when you walk in their office. If they put everybody where they wanted to work, there would thousands of personnelists, pilots, and medics, and nobody left to guard gates, cook meals, or fix toilets, but I disgress. Just ask yourself "what would I not get sick of doing for x # of years that wouldn't make me hate the decision to join up? What job offers bonuses? Who deploys to where & for how long? Do I get to go to school? Could I raise a family & do this?". Also, don't discount the Army or Marines. The grass isn't always greener on one side of the fence or the other. Good luck in whichever one you choose. They're all winners.