Some of them are flat out kick-ass. The best unit we ever had for our guard duty was a postal unit. They were incredibly high-speed.
The best shot I ever knew (with any weapon) was a mechanic with the 29th SG. Guy could nail a flea's pecker at 100 meters with a malfunctioning Bulgarian sidearm.
The thing is, you never know what exactly you're getting with a support outfit and many of them have combat-arms guys attached.
But if you've got nothing but a squad with a couple of Hummers and your basic-load for your M-16 there's not a hell of a lot you can do if you go the wrong way and end up facing an enemy platoon. That's just the way it is. I can't see passing judgement on those guys if you don't know them, their capabilities, or the chain of events that got them where they ended up.