Everything said is true but is that such a bad thing? Following the settlement system with Sim Settlements installed provides as much playtime as just following the quest to save Shaun. In fact many find the drive to find your son not as interesting as the rest of the quest and the plain exploring. Not to mention you can have more than one playthrough and play each one completely different. I also understand the crash issues on a play through with several hundred hours. Luckily I was able to save one of mine by giving up on one particular settlement after using tools and procedures here to destroy that settlement. Overall I think SS adds immensly to FO4.