Pros
The people are friendly and talented. Product collaboration is great - PMs and designers come up with cool new ideas, consult with engineers on feasibility and implementation strategies, and have open communication throughout the development process. Lumos has experimented with various team organizations and workflows over the years, and each change has helped improve engineer productivity. The codebase is well-organized so it's easy to navigate and work with, and it's also well-maintained - engineers clean up outdated code and aren't afraid to rewrite existing code to improve performance. There is a good pairing culture and meetings are usually kept to a minimum. There's catered lunch 4 times a week and the food is amazing. There's a good work-life balance; Lumos has a flexible vacation policy and people actually use it (maybe averaging 3-5 weeks per year?) There are also fun company-wide offsites each quarter, and a budget for individual teams to organize their own events.
Cons
Management and marketing frequently set arbitrary deadlines for new product launches, even before deciding what features they want to include or consulting with engineers about development time and potential concerns. Upper management tried to introduce a 10-5 "core hours, everyone in the office" policy. This came across as a lack of trust in employee work ethic and a lack of respect for anyone who wanted/needed to work outside of a 9-5 or 10-6 schedule (but on the plus side, many employees immediately pushed back and even though the policy wasn't officially rescinded, it also wasn't enforced.)