Pros
Keep in mind I worked there while Upshot was private, before being acquired by Advantage Solutions in late 2016.
It felt like your supervisor really had your back and wanted you to be successful- not just at Upshot but in your career. They provide ongoing training opportunities and don't just throw you to the wolves as a new hire. The atmosphere was fun-loving and collegial-- at least before Advantage came and implemented a more cut-throat corporate culture.
Cons
The employees are very young and very white. The hours are long, and there is a lot of pressure to attend social events and be a popular office personality. Also, because of their client Crown, alcohol does feature prominently at work events, even in-office. At the time, there was also no work from home leeway. Plus, the benefits were MUCH better pre-Advantage.