EzBoard has made lots of updates to their msg boards. They have boards out there with nearly 15,000 members and they run just fine.
If cost is an issue, if most people can pay the $12 to be an EzSupporter for a year then their page views will not count towards the daily views for the board, thus making the cost go down.
They seem to have done some nice changes over there and it is very user friendly.
And the first 6 months would only be $30 if it is paid BEFORE the board is opened to *the public*
Just a thought.
Good Luck...I'm sure if you decided to stay here and go with an upgrade that the members would make sure the cost is covered.