So I finally got a chance to play a Viking on Saturday, a VKG-3W.
It. Is. A. Beast.
When you get 8 hexes from someone and hit them with twenty SRMs after your companions had already brutalized it with lasers and LB-20X slugs.
I opened up on a Tempest in the second round, took out its Gauss with a floating crit, knocked it on the head, and ripped most of its right torso off.
The rest of the game it proceeded to march forward, blasting whatever chose to provide a target. I had some ridiculous cluster rolls, too: the one time I fired LRMs I hit with three of them and proceeded to get two 11s and a 12. I even used the LAC 2s- the Tempest was knocked out with 4 points of internal structure and no armor remaining on the Right Torso, so I used the only direct-fire weapons on the Viking to finish it of.