I have no issue with store brand/house brand oil as long as it's API-certified and meets suitable specs for the engine/application.
Would I run Supertech oil for 30,000 miles in a TGDI application? No, I wouldn't. But I wouldn't do that with AMSOIL either.
I've done weird stuff just to try it. When I had a 2010 Escape with a straightforward naturally aspired port injected 2.5L engine that would probably run fine on olive oil one of my most recent oil changes was "premium" Pennzoil Euro L 5W-30 in there just to see if there was a difference. Nope, no difference. Same fuel economy, same engine sounds, same responsiveness, but it was interesting/fun to put it in there. So while not worth it, it was worth it to me. My next oil change was "cheap" O'Reilly Synthetic 5W-20. It retails for half as much, and worked EXACTLY THE SAME.
What I'm trying to say is, you can put in oil that exceeds the requirements or offers more protection in theory, and you'll feel better about it. But in reality, your vehicle will end up in the junkyard for some reason other than a lubrication-related failure.
My next oil change will be on my new-to-me Chevy Volt which calls for Dexos1 5W-30. Guess what it's gonna get? O'Reilly Synthetic 5W-30. Yes, the most expensive vehicle I've ever owned, is going to get cheap oil. And guess what? This thing well end up in the junkyard in 10 years because the battery goes bad or someone runs a red and totals it, not because I used store brand oil.
All I'm trying to say is, have fun, use whatever oil tickles your fancy, but don't worry about what other people use because any brand of suitable oil will work fine for typical OCIs.