Pros
As employee of the London branch, I can see the amazing potential for growth, not just in the UK but in Europe. The office in London is small and you can feel the spirit of camaraderie. Good perks like a very interesting share scheme and incredible medical insurance. Also lots of opportunities for promotion if you want more responsibilities. If you like travelling, expect a lot (good that travelling is usually during working hours).
Cons
As the job is quite challenging, sometimes you find yourself completely absorbed and working late, while travelling, etc. (although the company doesn't expect you to do so). Great if that is what drives you, but it's not for everyone. On a different note, as the company is so new in the UK, the entire team is still "learning" and the on-boarding process can be tough. It takes some time to position yourself in front of the client with a strong knowledge of the company, its products and processes (which would be fundamental on a client facing role).