What purpose does the Evangelical Church serve?

Given the nature of these posts we can only speak in broad, sweeping terms and yet even this may give us some insights...
Do you consider yourself an evangelical Christian? Have you ever been to an evangelical Church, or have friends who are evangelical?
If so, what purpose do you think this 'arm' of the Church serves? Dave Tomlinson once memorably said that the evangelical Church was excellent for new believers but really poor once they had 'grown up' spiritually/theologically - then they needed to move to a 'proper' Church. Is this true?
I would love to hear your opinions - have you become an evangelical from another tradition or have you perhaps left the evangelical fold? Please tell us your story and perspective on this intriguing, beguiling, frustrating and energetic branch of Christianity...