Lot of good looking mirrors out there and the makers talk about how they are made but I wonder how you tell if a mirror has high quality glass and coatings ?

 

Buy a known brand, not a chinese generic mirror.
You get what you pay for.
A reputable brand will stand behind their product should there be any problems.

 

What style mirrors do you like? I think the HD mirrors have nice glass. Aftermarket I would have to say PM. Like S.D.M.F said just buy a known brand that matches your style and call it a day.

 

I am really partial to the cat eye mirrors from Ness. They are not giant, have convex glass to give a wide field of view out of a smaller than stock mirror, can be adjusted and "locked" in place easily and look good. IMO, a good mirror is almost not seen when looking at a bike. By that I mean, they will get lost and not stand out when viewing a bike; if the mirrors are standing out, generally it is not because they look good!