Nothing significant that I can really think of from a software engineer's perspective. No company is perfect but this company tries to be the best it can be and is willing to make course corrections. I've yet to see any communicated concern or request that wasn't taken seriously.
I would rate the compensation as "good".
The parent company is demanding and I think it's not always easy for them to see less headline-grabbing accomplishments/progress but the Imagine Learning executives do a good job of managing up to the parent company, and managing down to us workers / busy bees.
Those who require close supervision won't do as well here. Managers expect the individuals on teams to come up with ideas and solutions, and to help each other. If you're looking for the type of environment where a manager will give you highly detailed assignments, you may struggle. But for those who don't like being micro-managed and want latitude to solve problems yourself and with your team, this approach is exactly what you want.