I ran Kendall Elite in my 97 5.7 Sierra many years ago and liked it a lot. Back then, if you used the Kendall Elite, they did a free oil analysis for you. When I ran it I was up to 11,000 km's between oil changes based on their analysis.
I use to purchase it at a local garage, which was just one street over from me. Sadly, they quit doing the free analysis and we moved a year or 2 later and I have never used it since as I believe that is the only place around that carries it?
I don't ever recall seeing it at Wal-Mart or CDN Tire, but if I did, and it was priced competitively or was cheaper as it seems to be based on this thread, I would continue to use it.