I served in the Army as a commissioned officer for 12 years; then in the National Guard as a warrant officer. I was one of the lucky commissioned officers to go to the IP course while I was on active duty. I was a platoon leader, company commander, company and BN operations officer in the 160th.
Commissioned officers fly more now than in the past. Army Aviation realized it is not a good idea to take someone out of the AH-64 for 4 years, then throw them back in a unit as the operations officer. So while in the past an Aviation officer might go be a comptroller for 4 years (a military accountant), then come back and fly helicopters, that does not happen very much any more. Once you become a comptroller, you will never fly a helicopter again.
It's also born of necessity. If you have two pilots per airframe (not counting staff), and the airframes are flying 135 hours a month in combat... something has to give. Staff must fly. Still not as much as WOs, but still about 200-600/year in combat.
As a WO in the Army your primary job is flying and flying related jobs. Instructor pilot, maintenance officer, safety officer, battle staff (kind of an adviser to the commissioned operations officer).
As a commissioned officer you will be expected to perform your flying duties, and other duties as well. As a brand new 1LT out of flight school you will be put in charge of helicopters, pilots and crew chiefs. When I did this it was 5 helicopters, I think it is less now.
The Army has as many helicopter options as the Marines. You have the LUH (light utility helicopter, mostly in the National Guard at this point), UH-60, OH-50D (scout attack), CH-47, AH-64. Also, if you eat your Wheaties, study hard and do well, you can apply for the 160th where you can fly the MH-60, MH-47, MH-6. The helicopters are normally much younger and in better shape than the Marine helicopters. Nothing against those maintaining the Marine helicopters- they do a great job. Just gets tough to keep a CH-46 going after 40+ years.
The other advantage of flying for the Army is that you will fly with some VERY experienced pilots, especially on the reserve/National Guard side. Since we use warrant officers, you have pilots who stay in flying assignments for 20+ years. My co-pilot in OIF was a Viet Nam pilot with 18,000 rotary wing hours. You just don't find that anywhere else.
Also, with the Army, you have the opportunity to apply to the 160th after your first tour. Ask anyone in Special Forces, SEAL, Ranger, Green Beret, Pararescue, who they would want picking them up if the chips where down and the response will be unanimous. The 160th. NSDQ.