Pros
Passionate, inspiring team, inclusive & fun atmosphere, desire to continuously improve, great relationships with clients, time and money invested in staff. I loved working there and it's the only former company I've worked at that I would happily return to (if the role offered was right). It's a lot of fun (pool table and bar in office, annual overseas trip) but also perfect for collaborative people who are driven to do the best job possible.
I actually worked in the Singapore office full time, which was fairly small in comparison but equally fun. But I also spent a fair few weeks working from Marlow, which is a beautiful little town that's not far from lovely countryside but also not far from London.
There's even a club for past employees with invites to the annual party etc. Can't recommend them enough!
Cons
For me, the fact it wasn't London-based was the only reason I didn't beg for a Marlow-based job when I returned to the UK. It probably means salaries are fractionally lower than London, but so is cost of living.