Sorry you had a bad experience. I work in the Portland office and that hasn't been my experience at all. We have maybe 20-30 people and wide latitude over the projects we work on. Prior to this I had only worked in startups of 15 people or less. This experience has not been all that different for me, except that we're not constrained by resources. Our managers are former startup guys. It's honestly been great for me, to my initial surprise.

I've actually heard really positive things about Walmart Labs from the Node community.

They've even built and open sourced the popular framework hapi (http://hapijs.com).

Nearly every single one of those guys has left, and for very good reason. Ask around.