Pros
I've worked at FullStack Labs for 1.5 years as of this review. I believe everyone here deeply cares about our clients' projects in addition to the technology we use for them. When we're not working on client projects, we're researching (and building!) exciting new technologies, or debating JavaScript architecture on Slack. The company has a palatable culture of excellence and hard work. Each of us takes ownership of our projects. If you can keep up with changes in web technology and you enjoy development, then you'll be a perfect fit here.
Cons
Because we're a consultancy and not a traditional company, we have to put in some overtime — sacrificing the occasional Saturday — to meet client deadlines. We're getting better at this as we grow, but there's more work do be done in this area.