"A new concept in eyewear... Warby Parker was founded with a rebellious spirit and a lofty objective: to create boutique-quality, classically crafted eyewear at a revolutionary price point." http://www.warbyparker.com/our-story/
Given that Warby Parker are most likely using the same supply chain as their competitors, what exactly is their competitive advantage, to justify total funding of $50.3 million? It can't just be a prettier website, can it?
I've used several of the cheap Chinese glasses sites and the product quality all seems uniform but some of them have a better curated selection of designs than others. Warby also lets you do the 5 pair try on at home thing which I'd say is worth paying a bit more over the rock bottom price.
As far as the funding, I'd guess it's because they've been quite successful, and also because they're apparently in talks with Google regarding Glass.