Pros
Metric is a concentration of many of the most intelligent people I have ever encountered (professionally or otherwise). If you enjoy being challenged by people who make you think more rigorously, Metric Collective is the perfect place to work. You will have to put time into wrapping your head around concepts, and coming up with creative solutions to complex challenges.
Cons
Business here is fast-paced and won't wait for you to catch up at your own pace. (Unrelated): There is a lot of room for idea generation, but not always a lot of room for idea implementation. There won't always be an opportunity to chase down every project you'd like to complete. Most importantly, however, there is also an uncertainty about the social/cultural/political efficacy of the work done here. It is exciting to work on new products and problem-solve with people you admire, but you may find yourself wishing that you were doing more to fix the major issues that face our generation.