I work in London so I'll chip in. As others have said, rent is extremely expensive in the City however transport links are outstanding. I live just outside of

I work in London so I'll chip in. As others have said, rent is extremely expensive in the City however transport links are outstanding. I live just outside of London and pay significantly less rent than most of my colleagues who live in the City and yet it still only takes me 45 minutes to get to work, door to door. The start-up scene in London is arguably the strongest in Europe and there are tons of meet-ups and events to help you network. The jobs scene is equally vibrant. Rails is in huge demand with both start-ups and established companies so you'll have no issue finding work.