I've done a search, but it didn't give me much specific information about the two I'm considering.

BFG AT KO 285/55R-20

Toyo Open Country AT 275/60R-20

I was pretty well set on the BFG's, but the guy at the tire store actually recommended the Toyos over the BFGs, for various reasons.

All things considered, the BFGs, IMO, look better than the Toyos, and that's why I'm still leaning toward them, even though I surely expect an eye-roll from the guy when I say so.

I have a 2005 F150 Lariat 4x4, do pretty much 100% road driving, and will put these on 20x8.5 wheels.

If you were in my shoes, which would you choose and why?

 

Both are excellent tires. If you like the looks of the BFG's better, go with them. Personally, I like a wider tire so I would probably choose the BFG based on them being 1/2 inch wider. Maybe your guy has a higher profit margin on the Toyo's.