Pros
Very capable, motivated, and humble engineers, especially ICs. We've had our ups and downs but in general the bar has stayed high, and the quality of people brought onboard is terrific. Varies from team to team, but in my experience you can ship things as soon as they're ready, so long as you have a plan for an experiment (design changes are harder, though). I've found lots of opportunities to learn from co-workers and work across eng teams. Enthusiasm for open sourcing. Great new building. Engineering restructures in 2015 help organization move fast. Ben really cares about building a healthy culture, listening to employees, improving based on his feedback etc. Product has incredible potential, which in general keeps the company moving and inspired, and negates many of the concerns.
Cons
For better or for worse, company is product and design driven. As an engineer, you have to convince yourself that at its core, there is impressive technology built here powering the ship. Once you get down to the eng. manager and IC level, company is innovative from a technology standpoint. But don't expect all-hands to give in-depth kudos or highlights or even any particular acknowledgement of the engineering work done here. Focus is all on product, users, design. External engineering brand suffers, as a result.