That's a decision for you to make. It all depends on what you want out of it, perhaps where you want to be stationed, etc.
Of the list that you have provide, the marine corps infantry is the best.
A soldier is someone who is in the army. A Marine is a person who is serving in the United States Marine Corps. What you are probably referring to is an infantryman or someone who is a member of the Marine Corps Infantry.
For the US Army, during the Vietnam War, a battalion was about 600 men. The US Marine Corps will be similar in organization (during the Vietnam era).
The order of battle of invasion troops for OLYMPIC/MAJESTIC were 14 Divisions: 10 Army Infantry, 1 Airborne and 3 USMC equal 450,000 combat and support troops staged at Okinawa.United States U.S. Sixth Army Yakushima and Koshikijima Islands - 40th Infantry Division (22,000 men)Tanegashima - 158th Infantry Regiment (7,600 men)Miyazaki - U.S. I Corps (95,000 men): 25th Infantry Division, 33d Infantry Division, 41st Infantry DivisionAriake - U.S. XI Corps (113,000 men): 1st Cavalry Division, 43d Infantry Division, Americal Division, 112th Cavalry RegimentKushikino - U.S. V Amphib Corps (99,000 men): 2nd Marine Div., 3d Marine Division, 5th Marine Division6th Army reserves - U.S. IX Corps (79,000 men): 77th Infantry Division, 81st Infantry Division, 98th Infantry Division;11th Airborne Division (15,000 men)
The Army's birthday is 14 June 1775. The Marine Corps' birthday is 10 November 1775. The Army is older, by 4 months, 9 days.
Army...
Commander is a rank exclusive to the Navy. It is the equivalent of an Army/Air Force/Marine Corps Lieutenant Colonel (O5). A Navy Captain is equivalent to an Army/Air Force/Marine Corps Colonel (O6), whereas a Captain in the Army, Air Force, or Marine Corps is O3. A Navy Captain outranks a Commander, but a Commander outranks an Army, Air Force, or Marine Corps Captain.
The United States Marine Corps and has never been a part of the U.S. Army. It is a separate service that falls under the Dept. of the Navy.
Yes, but it was from the U.S Army and not the Marine Corp.
Infantryman. Without the infantryman, there would be no army. Tanks support the infantry; Artillery support the infantry; aviation supports the infantry; Military Police, Food Service, Medical Corps, Pay Master, Administration, K9 Corps, Transportation Corps, Engineers, JAG, all support the American Fighting Man...the grunt.
Complete your contract and see an Army recruiter.
You'd have to wait until the end of your current enlisted, if you're currently enlisted in the Marine Corps on active duty. If you wish to go from the Marine Corps Reserve into the Regular Army, that can be done, though.