I use my own 90% of the time. As with the store bought ones, I too have spent countless hours crafting them and I like them a whole lot.
People often will buy me some rubs and sauces they find,and I occasionally buy some myself. I'll use them here and there, or when I'm running low on my own stuff and don't have time to make more for a week or two.
But at the end of the day, I developed my 2 rubs and sauce to be exactly what I want, so I do prefer them to just about anything else. Plus, as a competitor I like sing to take the credit. I can't imagine winning an award using something that I didn't make.