I have the polished units. I haven't noticed any glare or reflection in my mirrors. Powder coating is very durable, but it can be scratched or chipped. Other than touch-up paint, or, possibly, a light buffing using a very light compound/abrasive, you can't repair powder coating. I went with the polished because it's easy to rejuvenate the luster using a buffing wheel. Light scratches can be sanded out and re-buffed. Very little effort is required to make them look new. Plus, I like shiny stuff and the polished goes well with my truck's chrome. Mainly, I'd say aesthetics played the biggest role in my decision. Cost difference wasn't a consideration.
P.S. As a side note, the powder coat on one of my rear TorkLift tie-down brackets has been cooked/melted by my exhaust. Rust has ensued. I'm not surprised. The front brackets remain on the truck (they're not kneecap-busters like the rears) and still look good (enough), after 15,000 miles.