Pros
There's a great vibe in the office - lots of really experienced people having fun at their jobs. Lots of autonomy. The offices may not have exposed brick, but they are quite funky - a loft-style kitchen with free fruit (and various people bring in cake, choc-ices and other fun stuff). There are some good social events, too. Most of the office is hotdesking (with lockers) and many people do a day a week from home.
Cons
None that I can think of.