Fair warning: more rambling than usual. Listen to my thoughts about SEO. What I think I know is that SEO is a series of fairly obvious best practices. A SEO service that helps you with those things can be good, a SEO service that claims to do anything else seems shady. However, there are plenty of examples where seemingly doing everything right doesn't seem to work, and results that show up higher than your project look like pure garbage. SEO is, and may always be, quite mysterious.