I've been looking for a tier list, as our academy only bans tier 1, and this is the only one I've been able to locate. It seems pretty reasonable on how it judges tiers, so I mark it as pretty acuurate. See for yourself.
http://www.pojo.biz/board/showthread.php?t=1150442&highlight=tier
http://www.pojo.biz/board/showthread.php?t=1150442&highlight=tier