Fantastic company to work for, with some strange flaws
Pros
Fantastic working culture - doing agile the right way. Strong emphasis on professional development. Because TW works in small teams in client sites, you will be freed from much of the hierarchy that it present in a normal business. You will also be able to take on stretch roles that you'd never be able to get into in a normal business. Company is very open about finances and releases summaries to the entire business. Strong focus on working with people - I learned a lot about soft skills here. Fantastic internal training program for graduates ("TWU")
Cons
Annual review process systematically disadvantages those unable to game it. Company political stances (socialist/progressive) sometimes go overboard. The travelling can be unsustainable - it's even worse in the US. The loss-making parts of the business can sometimes cause wider belt-tightening. Occasionally I thought about sectioning members of the senior management team under the mental health act.