Pros
I've been at Avalara for several years now and as time goes by I love this company more and more. We are literally on the cutting edge of a basically green field; sales tax automation. The problems are challenging and yes it's sometimes difficult when you're the one cutting the path, but I'm excited to see where we are going as a company. If you like a fast moving start-up, high level of responsibility / ownership type environment, you'll like it here. If you like to conceptualize and bring to reality truly complex, beautifully coded software, you'll like it here.
Cons
There's been a lot of exciting progress but there's a lot more work to do. It's not really a con as it represents opportunity to come in and actually build something that will affect a lot of users.