High-octane ethanol vs. non-ethanol?

[PathfinderNI]

Just wondering guys......last time I took my 4-stroke Yamaha in for servicing at Trails Yamaha in Henderson, a couple of the heads were underperforming big time. Owner told me that normally at this stage the heads are shot. He did a shock treatment I suppose with ring free and got the compression back down to normal percentages. Anyway, I asked him what caused the problem and he said bad gas. I asked him if I needed to be using non-ethanol and he said that would be even worse than the low-octane ethanol I had been using! He said there was not enough oxygen in the non-ethanols anymore and that he recommended 93-octane from Shell or some other quality name.

Thoughts??