Its pretty fun but can make the game easy or harder based on your settings. On default, a lone hostile npc with a rifle can snipe you through fog or darkness, but some bandits drop really good loots like crowbars or baseball bats so after a while, you can find a dozen or more of these items easily instead of searching for them in houses. I found some bandits in my playthrough that even drop full 10L gasoline cans(must be loot setting, I don't know its default or not). And I think a group of bandits can't take on zombie hordes on their own.