I was frustrated to see that whenever I wanted to join in multiplayer, all of my invites were for open beta and I have 2.5 stable. I personally feel that as the beta version will always be an ongoing development, that the need for a stable version is irrelevant. If as is said, the beta version is a test bed and any problems are sorted which I think is fab, its just like having the full game and having patches to update it.
So whats the point, if you play single player or multiplayer, keep just the open beta and keep fixing it as we go along. I will be downloading the open beta as soon as possible so I can fly some cracking multiplay and also benefit with the modules I have.