What are the advantages of being bootstrapped and not VC backed?

You have more direct control over your product. Whereas with being VC backed there is that expectation to do what is considered "profitable" by their own metrics. Granted, bootstrapping is a long and arduous process, but I think the trade off would be worth it, as you would have the final say.

You grow steady and strong. You're less likely to go out of business, because you know how to stretch a dollar.