Pros
Cell Press is full of amazing, motivated people. They work extremely hard and have a culture of pitching in - everyone is willing to lend a hand. They care about getting feedback from across the organization and do a lot of cross-departmental projects where representation from all tiers of the company is important. There are opportunities to take on more responsibility early in your career. Working for Elsevier is a mixed bag, but you learn a lot about the publishing industry as a result, and working for Cell Press helps to mitigate against some of the worst parts of Elsevier.
Cons
Salary doesn't progress well, particularly for people who are promoted to take on more responsibility. The company is usually willing to let people walk rather than pay them for their enhanced skillset. Their benefits got worse every year and their concern was always making sure they weren't an outlier in the industry, rather than making sure their employees were well-served. The workload can also be a challenge - if you don't like being busy, this probably won't be a good fit.