I'd say the definitive "what is better" would be the pay, and the responsibility/satisfaction of performing the job and accomplishing the missions.
As a sergeant in the Army, I was pushed and a lot was asked of me compared to a solider E-4 and below. In the Army the rank structure is such that the biggest difference in the enlisted ranks is at sergeant, everything below is a "soldier" (well, everyone is a solider in the army, but in this context hopefully you can understand), and everything from E-5 to E-7 is called "sergeant" regardless of actual rank. E8/E9 is either master/first sergeants and sergeant/command sergeant majors respectively.
So the big "gap" in the army exists between E-4 and E-5, where in the navy it seems to exist between E-6 and E-7. There's a big distinction with being a "non-commissioned officer" in the Army. Much of the physical labor stops when you become a sergeant, not that it goes away, but you are expected to lead your troops to accomplish a mission, not do it yourself. This is not an Army vs. Navy post, I don't think either rank structure is better, but they are simply different.
What this means is that the E-5s to E-7s run the Army, are responsible for the soldiers, equipment, the mission, and a plethora of other duties. You are in charge of people and equipment, and you are expected to be a good leader. When went to leadership school in the Army and became a non-commissioned officer, my job did not get easier, it got harder. I had to perform to a higher standard, show my soldiers that they should follow my lead. I had to be a father to them in many ways, I had to discipline them when necessary. I had to counsil them, and on top of that I had to do my mission related duties. The dreaded "paperwork" also started
. I was in charge of a battery fire direction center, and my was on my arse whether or not missles ended up at their intended targets, and if they did not, they could fall on civilians or even our own troops. Lots of responsibility, lots of satisfaction though from accomplishing the mission and making it all work.
For my essay on why I want to be an officer, I am using similer themes. I want to take this to the next level. I know it will not be easier, it will be harder. I'll get my rear end chewed out when things don't go right and there is a problem with "the mission". I will be responsible for even more people and equipment, and I will have to mentor and lead other "leaders" who are themselves in charge of people. It's a challenge, and it's an evolution. It's a "push" that makes you perform to an even higher standard, one that you may not have thought was possible beforehand.
So pay and benefits are hands down better, but it's not an "easy" job.
Think about it in terms of life-after the military, a company is going to look for the best leader/manager possible, so the more responsibilities you had, the better performing your section/troops/sailors were, the higher the rank and more important the missions, the more likely they are going to want you managing their own people. In other words, I'm in this to "go as far as I can go", "do as much as I can do", and you know the last part, but I won't say it.
