I finally got a chance to get my Alpha Legion on the table with the Traitor Legions supplement, and dude, they are so much fun. I narrowly beat an Ultramarines Victrix Strike Force with Roboute Guilliman, because, while I wasn't able to come close to matching his combat power (he utterly destroyed everything he made contact with, including my Terminators+Chaos Lord and Sorcerer, which he downed in 1 Assault Phase), massed Infiltration let me control the board well enough that I was able to stay on top of the Objectives and keep the lead.
Mindveil did totally betray me, tho. The one Turn I really needed it, I
only ended up getting 5" of movement, when I only needed like 9" to be
able to get away from Bobby G.
On the other hand, Many
Heads of the Hydra (or as I like to call it, "I am...NOT Alpharius)
saved the Game for me by preserving that Warlord point, which ended up
being a big deal, since the Game came down to a 1 Point difference at
the end. Very fun Game, one of the best I've had in a while. Definitely
looking forward to getting them more table time.