I notice (aside from bots, vehicles and hovercraft having different movement strengths and different amounts of health) that there are "unique" units for each build type - Armada bots have tumbleweeds and there is no equivalent Armada vehicle. Indeed perhaps there is nothing like the tumbleweed in any other factory? It might be useful to highlight these "specials" in some way on the website and in-game?
It might help beginning players to see at a glance how the factions are different and to know what they are "missing" if they go with just one vehicle type not another. Naively I thought at first that there would be an equivalent vehicle for each bot unit at any given tech level. It's good that there isn't, frankly, as it would make for a duller game.