One of the most important factors for me is that they also offer an option to make the lens thinner because my prescription is quite heavy and without that feature, my glasses would probably weigh like a brick on my nose. Last summer, I switched to my current pair, the Milton in Brushed Navy--best decision ever. The nose pads help them stay on my nose longer (I have an Asian nose...they just don't hold up well with the plastic kind). Anyway, I love the round frames on my square face + I wear them all the time. *Totally worth the money*
If you are not close enough to visit an actual Warby Parker store, you can visit the website. They have a home-try on system where you pick your faves, they send it to your home, you try it on, buy the one you like, and send the testers back. It's a lot easier, of course, if you can go to the store since they have salespeople (so you can ask questions) and usually the full selection of glasses AND sunglasses.
The glasses range in price from around $95 to $195 but add-ons will cost a little more. Return is really easy. I've had to do a couple of returns when I realized the frames don't suit my face. They can also help you do exchanges as well.
Okay okay, I'm done ranting. Here are a couple of my faves right now (and currently thinking about getting).
More info: here
More info: here
More info: here
More info: here