Pros
I'm giving 5 stars because I do think Twitch is a great place to work. Most of the Glassdoor reviews are polarized, either Twitch rules or Twitch sucks. I'm not sure how helpful that is so here are two observations~ 1. It's a product-driven company. CEO is a former engineer turned product manager. If you work in engineering, UX, or any function that directly contributes to product, you're highly valued. If you're in partnerships, customer support, marketing, or any other function you'll have a harder time getting things done. 2. Engineering quality varies massively by team. Some managers are running a tight ship and others just let their engineers do whatever they want. Seattle is corporate, Irvine is the army, and San Francisco is wild west. If you're thinking of joining, great, if you like the team you'll be working with Twitch won't let you down.
Cons
Enough said, read the section before.