Loaded question, it's all about marketing and developing brand loyalty.
Use the recommended oil and change it when your supposed to.
from Blackstone Labs,
What's the best oil to use?
Ah, the million dollar question. We are an independent lab, so we don't make recommendations. It has been our experience that oil is oil, and either petroleum or synthetic-based oil will work well for just about any engine.
Come on, you're holding out on me. I should use synthetic, right?
Buddy, you should use whatever you want. Synthetic oil won't guarantee a longer engine life any more than my eating organic food will guarantee I'll live until I'm 90. We here at Blackstone generally use regular petroleum-based oil because honestly, it works just as well for us.