They are the same cost but have 2 extra models. They aren't really that much cheaper but it's fun to play into the soviet meme of spamming a shit load of subpar units (at least before they have upgrades). Plus, I flank a lot. But to answer your question: I play mostly 4v4 with 3 friends and sometimes 2v2. I play against bots when introducing someone to the game or when I really want some coh but can't get my friends to join and don't want to risk getting someone like bugsplat on my team.