In-house frontend web developer

Before I begin, I would love to know what you think on this topic, because it is a subjective matter and really only you can decide what works best for you. So please leave a comment with your experience and thoughts on which type of team/company you prefer to work with.

I would like to make clear that I am yet to fully decide which is a better role, being an in-house frontend web developer or being a web developer in an agency, and I am still gathering my experience in both areas.