Pros
I was mid-level employee in the communications practice. I took the job after 4+ years working in the political world and didn't think I would stick around long doing corporate and policy communications but ended up staying 2 and a half years because I enjoyed the company, the culture, and the work so much. If you're willing to work hard and work well with others, you will not only succeed here but you will be rewarded for good work. As a mid-level employee I often had face time with company executives which I've heard is not the norm for mid-level employees at other similar firms in the DC area. The firm is truly a flat organization in that the company's executives make sure that mid-level and entry level employees are deeply involved in client work which I have also noticed is not the norm at similar firms in DC. The firm is owned by a larger law firm so you're able to get the benefits of being with a large company (free lunch once a week, free snacks, beverages, etc.) but you also get the benefits of a smaller/mid-size organization (more intimate office environment, ability to rise in the company more quickly etc.)
Cons
There is often a lapse in communication internally within the firm and occasionally organizational issues from a management perspective, but I think all companies experience these types of situations.