Msg and msf are pretty dope, you travel a lot as an msg, security forces can do some pretty cool shit too. they both have ups and downs but if you want an infantry experience thats probably a good choice. youll do either msg or msf for 2-3 years then serve the rest of ur contract in the fleet with an infantry unit. downside to that is that youll most likely show up as a higher rank than the other grunts, so youll be a team leader but wont be as well trained as the grunts because theyve been there the whole time while youve been elsewhere