Rba
I would encourage you to check in to the RBA, for several reasons.
The Rimfire Benchrest Association is not privately owned, it is made up of members. So, there is not one person who can say "we are going to do this" or "we are going to do that". Rule changes are voted on by the Match Directors. I also like the fact that the target is a little more challenging than some of the others.
There is somewhat of a misconception that RBA is a 3 gun organization, which is absolutely not true. There are more unlimited targets shot each year than 3 gun. In unlimited you shoot any 22lr as long as it is not attached to the bench. No weight restrictions, no rest restrictions, no stock restrictions, and no scope restrictions.
But what I like the most about the RBA is that it is a non profit organization that pays it's members back at the end of the year in money and prizes. Last year there was over $6,000 in cash and prizes given away to the members based on where they finished in the RBA Standings. Prizes include things like barrels, stocks, triggers, cleaning rods, shooting stools and so on. So, if you are going to compete in something as expensive as rimfire benchrest, why not shoot in an association that pays you back.