When it comes to combat skills, how well trained are Support and Service Support MOSs?

All the Infantry does is train in combat. So you won't get what they're getting. But you should get some. Everyone should be able to operate in a combat environment which means operating and employing weapons systems. Support MOS' will focus more on reactions to enemy contact versus Combat Arms who will also train to take the fight to the enemy.

As a 91b you can get sent anywhere and everywhere and go out into the field often.. based off your unit. Some places go out every month to train

This is my experience. I joined up as a 63b, now 91b. I went to Afghanistan in 2004 and when I was there I got sick of the motor pool and went and talked to my 1sg, I asked him to buy me on the patrol team as a "team mechanic" because I wanted to see action while I was there. He obliged me, while yes I did conduct maintenance operations I was also a fully functioning soldier. I did many jobs in the patrol team. I started as a driver and made my way to .50 cal gunner and finally to dismounted security/patrol. I was in a field artillery unit and the entire unit, even the pac office did combat training. When I got back, I was looked to for advice in combat ops when training new soldiers. I'd been complemented by op4 and the command when employing things I'd learned. Not everyone will have the same story. But this was my experience. When I went back to Iraq they kept me in the motor pool, my second tour in Iraq, they sent me to a small forward. The armies like a box of chocolates, you never know what you're gonna get. Train up on your personal time, it could save your life. If you never use it, so what, you still learned something.