Pros
People are amazing, hard working, smart, organized, passionate, fun, dogs are allowed in the office, flexible working hours (where possible), training available, loads of snacks, coffee and great office space, cross office working is great on a couple of clients, lots of opportunities if you work it right and some great clients (if you get to work on them).
Kontras
You are always expected to do the role above the role you are bought in to. Same issues as in any agency in regards to not having enough people to do the work. Everyone gets stretched, everyone has to cover to do work, or when people leave their role, as hiring takes a while, it has to be picked up by the team. If you are not outgoing or very driven there is a chance you may get forgotten and will stay on the same projects/work. Quite tough to move between clients as usually you end up 'owning' the brand as there is not one else who has worked on it. Just a watch out to make sure you push to keep your portfolio broad. Usual agency turn over as a result.