Pros
There are really only two reasons to work at Bonterra: The people and the mission. The people are generally excellent: Passionate, knowledgeable, and friendly. The further away you get from the executive level, the more true this is. The mission of the company, while diminished, is still an important one. Their software is critical for Democratic political campaigns and non-profits, and the people at the company are proud of this fact (as they should be). If you are a junior engineer, this company can be a good fit for a short time, especially if you are passionate about the space. There is a lot to learn and Bonterra still (for now, at least) has a number of experienced people who are happy to help you mature in your career. Note: Be wary of other positive reviews here that are skewing the average. Many have been paid for. I wouldn't automatically discount any positive reviews, but if they don't have any details, or contain obvious nonsense ("Communication is well-maintained, enhancing both efficiency and safety."), don't believe them.
Cons
Bonterra is a Frankenstein company assembled three years ago by a private equity firm out of four companies that have almost nothing in common aside from having non-profits as clients. While each legacy company had its own culture and mission, Bonterra has attempted to assimilate the new organization through force. Ultimately, however, the mission of "make money for our investors" and a culture of toxic positivity pales in comparison to how things used to be. This has ultimately resulted in two different classes of employees. The first class are people with low expectations. They don't question management and often don't come from the non-profit world. To them, the job is just a paycheck and questioning management is tantamount to insubordination. They either have never been at a company that treats them properly, or simply don't care as long as they have a job. Some of these people were brought in from the CEO's old companies specifically because of this viewpoint. In general, these people toe the company line and appear to be happy with the way things are going. If this sounds like a place you want to work, then Bonterra might be for you. The second class are legacy employees from the original companies who remember how things used to be and are frustrated and angry at how Bonterra has failed them and their clients. These employees are knowledgeable and passionate, but have been ignored and marginalized. They want to work at a company that values their experience and sees clients as partners, not paychecks. They want transparency, to be heard, and accountability from management. Unfortunately, that's not what Bonterra is any more, and these folks are often torn between desperately wanting to serve their clients and their important missions and an organization that is stubborn, arrogant, and ignorant. If you have read the other reviews, you see that there is a resentment between the first and second class of folks. I predict the first class will eventually triumph through a war of attrition. Of course, in this war there will be no real winners - the clients will suffer, the employees will be miserable, and the investors will (deservedly) lose their investment.