It is definitely heavier on the tower defense side. I also usually turn biters off in Factorio, but I found that Mindustry to be well balanced between the logistics and tower defense aspects. You have to build up both constantly, unlike Factorio where you just over build defense and then wait for that to fail before thinking about it again. In Factorio, defense is a nuisance mostly, but Mindustry it's integral to the gameplay loop. Not sure if that answers it for you. I don't think I'd recommend it unless you wanted that aspect of the game.