I have only had my truck for a month and haven't even filled the tank up yet so I can't say how it is for the engine other than the manual says B20 is fine.
I do know that in our large backup generator at work we run non-bio. I worked with our utility company as they have several standby/peaking generators that they run. They have had issues with Bio when it sits longer (water and bugs) and plugging filters in cold weather. I have had fuel sitting in our tank for 2 years without issues.
In my opinion, run whats at the pump if your manual says it can run it. If you are going to let it sit for the winter try and get something with out, or as little bio as possible to prevent issues while sitting.
