1.) Absolutely not.Do you think the ODs at a giant corporation like Lens Crafters and Wal-Mart are less capable than the ODs who work for a giant corporate healthcare management system or a group of MD/DO ophthalmologists?
Just make sure your frames are comfortable. You shouldn't notice that you're wearing glasses.
I was thinking more along of the lines of chain vs. non-chains.
Just like choosing to get your medication at CVS/Wal-Mart vs. a non-chain independent pharmacy, your medication co-pay is the same regardless of where you go. If the prices are the same, why not go to the independent and form the personal relationship? I certainly don't think that pharmacists that work at independents are more knowledgeable than those that work at chains. In this case since I don't have vision insurance, but I will have to shop around on prices and read reviews.
2.) How does one determine that in 10-15 minutes while trying them out? For something you may be wearing all day 24/7 I'm not sure there's a way to know that. Do these glasses shops have a returnable/exchange policy if you're not pleased about the comfort after a week or so?