Pros
If you're coming to this site because you're considering applying/joining Sourcebooks, I would encourage you to read through all of the reviews here (minus the planted 5-star reviews). Taken together, they'll give you a pretty good picture of the culture and environment. The upside is that there are a lot of creative and passionate people at Sourcebooks. I found that most people truly cared about their colleagues and wanted to help each other. The company takes time to celebrate company successes often which helps with team morale. No matter where you are in the company, you will be constantly challenged to learn new skills which can become useful resume fodder. But that's where the positives ended for me.
Cons
Individual experiences will vary depending on who your manager is. There are some great managers and there are some not-so-great ones too. Trust your gut if you interview for a position and have any misgivings about the people who would be managing the role. In general, there's a culture of chronic overwork at Sourcebooks. It's not just that the workload is ridiculously high (it is), but those who stay with the company long enough come to consider it a point of pride that they are constantly plugged into work. It's not healthy. Combine that with the fact that the company offers only the minimum in terms of paid holidays and PTO, and burn out is common. Turnover is high. HR managers never seem to last very long. Every single day is stressful. Many are severely underpaid, especially considering how hard they work; some of the younger staff have to work second jobs to make ends meet. For many roles, Sourcebooks likes to hire people fresh out of college, especially ones with big dreams of working in publishing. These young staff members don't have a lot of work experience yet, so they don't recognize how dysfunctional the culture of Sourcebooks is. Some stay, but many figure it out (or are pushed out) and move on. The company is constantly evolving, so the "ladder" you start on could change at any time. Getting promotions can be hard in certain parts of the company, just depending on the department structure. At a certain point though, growth and advancement opportunities will be dependent upon your willingness to put in a lot of extra time at work and to really buy-in to the culture. Even though everyone has laptops, the company strongly discourages any work from home, so expect to be commuting into work even when the weather is bad in winter (or else being forced to use your very limited vacation time if you simply can't make it in). There's not much flexibility in terms of your schedule, either. Overall, it's a very rigid, regimented environment.