This is the 3rd game of the tournament yesterday. I, of course, used the same list. My opponent was playing Vanilla Marines. He had a drop pod with lysander and 10 sternguard, a unit of assault terminators, led my the Chapter Master (can't remember his name, but the guy with 2 power fists), 3 vindicators, and 3 squads of tacticals.
I won this game by a large margin, primarily because I out-maneuvered him (although almost messed it up on the last turn by charging his unit away from an objective with my cultist, instead of the unit toward objective - had the game gone another turn, I would have had a minor victory instead of major). He dropped the pod and terminators behind my ADL, and swept through my back field, whereas I deep-striked everything with a 2+ save behind his lines.
In this game, my Helbrutes contributed by being roadblocks that he had to assault to get to my troops. They still died without killing anything, but by forcing him to charge them instead of my marines, I bought my marines 2 turns (which left me with an objective I wouldn't have had, and would have lost in 1 more turn).
My terminators and oblits landed behind his lines and took out 2 vindicators, and my autocannon heldrake killed the other with a side shot (I am liking the flexibility of having 1 each weapon on the heldrake). The fact that I was able to take out 3 vindicators in a turn is re-enforcing the fact that the helbrutes are superfluous in this list, and can probably be replaced, maybe with bikes or more terminators.
I already knew I would have a hard-time against terminators, but my plan of staying away from them worked, and I don't know of plasmaguns would have made much difference against stormshields (although, if i hadn't needed to kill the vindicators, I could have dropped plasma cannons on them). The only problem is, you can't stay away from them, if you need to hold an objective, so I might need more tarpitting (thinking more of zombies)