Pros
ZURB is a place where you will learn a little about everything that comes with the design process. You'll learn how to communicate with clients, iterate on designs and code. The people are fun here and want to learn and there are some decent benefits (free food, insurance, new building etc). I am a better designer because of ZURB.
Cons
Although ZURB does help people become better designers/engineers etc there are just too many cons. ZURB is working on too many things. There are only 20+ people in the company and they are working on client work, ZURB's own products and internal sites so burnouts come very quickly. You long hours and are always expected to do more. The compensation is also very low compared to other places you can work for as a designer. When you try to express your concerns ZURB says they are working on things but nothing really happens and because of this a lot of people leave. People don't stay very long here and ZURB is constantly having to hire new people to fill the gap.