Pros
The people who work at Kepler are the best you will meet in the industry -- incredibly smart, hard working and outgoing. Majority went to top tier colleges, are type A, are very competitive but are sincere and want the person next to them to succeed as well. If you are considering working here, you need to be very interested in digital marketing to succeed and get promoted. At lower levels this means working 50+ hours a week. At higher levels this means putting on as many hats as possible -- being best friends with the client is practically mandated. Leadership is overall great (Rick does a great job and is more transparent about the inner workings of Kepler than any other CEO you will encounter at an agency) and does a good job of showing their employees that they care about them and are willing to change things to keep them happy. Culture is strong, there are groups for anything you are interested in which makes making friends / expanding your network pretty easy. They put a lot of emphasis on culture and will put their money where their mouth is to make it a reality (monthly company happy hours where all levels are present, weekly all hands meetings, monthly pod budget to go out with your team, talent shows, competitions etc.). There are also less internal politics between departments here than at other large agencies / holding companies.
Cons
Extremely steep learning curve to learning their internal tech. Constant shuffling of the accounts you work on create a sense of "why bother to learn if I'll be on a different account in 2 months". Unacceptable amount of tribal knowledge on accounts. Majority of the account learning you do will be a treasure hunt (gleaning old decks, talking to x person who tells you to talk to y person), although their 101/201/grad school trainings are relatively good to learn the industry basics. Just about every problem is approached with a "create a google doc and have a meeting" solution. No cohesive/standardized process across accounts makes things feel up in the air at all times. Side projects are a mess because some teams/employees are overworked, yet still tasked with them. Majority of type A people at the company results in an emphasis on the most vocal being rewarded. Just like the pros, you have to be honest with yourself about how interested you are in digital media to succeed here. You will be tasked with learning multiple channels, partners, platforms, ad ops, etc. which can be intense. You'll be asked to push their partners agendas (if you question the partner kool-aid, it falls on deaf ears internally). You'll be asked to speak in front of clients (regardless of title) and in front of the agency. Some candidates love that, some don't.