I get that popup about the out of date driver as well and I'm on 16.04. As far as buildings go, I'd say you'd prefer the multiplayer arena matches because you can build buildings to unlock your tech tree in those battles.

My own favorite is "The Last Stand" which actually suits L.G.C. perfectly because three of you go in and try to defeat the A.I. waves of enemy. Hard at first because you need to level your characters. The Bloodied Colosseum is the best one to get started with. Once you've leveled to 20 you can move on to "The Anvil of Khorne" for more of a challenge.

And the good news for Jordan is you can play the Necron and Tau in this game mode provided you have the DLC.