I was a Combat Eng. in Afghanistan with the US Marines.
First of all, when you become a Combat Eng. you can see one of 2 things:
1) No fighting i.e base work
2) Fighting that would rival WW2
As for me, I only saw 2 fire fights in the 3 weeks that I was in Afghanistan(a member of my family died and I was flown home)
We were building a control tower on one airbase in the western part of Afghanistan, and those idiot Taliban soliders felt the need to shoot some AK and RPG's at us(the didn't hit us)(that lasted about 5 min)
We were getting on a helo and a AK-47 burst came out of the bushes, the helo took off, and we exchanging about 10-20 mins of fire, and then that was over.(nothing major)
As for me, I wanted to be an Eng. to help people and kids of war torn countries, not to kill people(but if my job was to kill people I would do it)
Do you have much control over how much action you see? I want to do something that will put me into the battle and also provide good experience after the Marines. I also heard that combat engineers get alot more respect than grunts and they also get to play with C4 lots of fun.