What kind of sniper?

Alright, so Im wondering what kind of sniper/sharpshooter I should be? Air Force, Marines, Army, Guard or SEALS...who can tell me what the differences are between them (not who's better) with issues like what they do...is one more mission orientated than another does one do more recon than another, is one more defence, etc.... please dont comment me back saying I cant do it, I need to be a C3 soldier, have to work my way up, slim chance, danger danger, patience, can u kill a person, yadda yadda I already know all about that...I've thought about this job for a few years now...I know it's extremely dangerous & unglamorous, but that doesnt matter to me I love my country and I have a calling to do it...Im not in it for the money or the glory (which is very little anyway) I'm going into it to save lives...so ANYWAYS...what do different snipers in different branches have in differences?