A few years ago, I played on an excellent competitive TF2 team that won ESEA-Open and lost ESEA-Intermediate in the playoff finals. Some of the players that played on my team actually went on to play in invite as well. For those who don't know, ESEA was the only (maybe still is) paid league for TF2 and had the highest caliber of players.
Our old ESEA team page:
http://play.esea.net/teams/42600
Frag video from ESEA-Open:
http://www.youtube.com/watch?v=EIzQLlA9zQ0
Frag video from ESEA-IM:
http://www.youtube.com/watch?v=w6jROGEuZXw&hd=1
