If you want to be infantry go Army. The Army offers more in the way of schools like Airborne, Air Assualt and Ranger. I was enlisted as a armor crewmember on Abrams tanks for the past six years and loved it. I fly Apaches now all thanks to the Army and giving soldiers every chance to improve their lives.
But what everyone else has said is true, you will spend time, lots of time, away from your family. You will work harder and longer than you ever thought you would and you will get treated worse than you ever thought you would. I loved the life on the ground. I deployed with the 82nd Airborne and spent 15 months kicking in doors with them. It was great. But there is a awesome feeling rolling through the worst streets in the world feeling invincible inside your tank.
A wise old NCO once told me, "if you arent getting everything out of the Army the Army is getting everything out of you..."