At least if you have to optimize both, how the term fits to the current state and how the interpretation of the term by an average visitor fits to the current state, beta is best.
Most people interpret beta as "playable yet unfinished". Any term they do not know they might ignore, or it might make them fear that the game will mess up with their whole windows installation.
I'm not here as often as I used to be, but I do definitely notice there's a thread every now and then where someone states that the game is ** (not knowing that it is not even close to a final), and then some people take fun out of flaming them. Something should be done, either against the people who don't notice the game isn't done yet (by making it more obvious, as suggested by the op), or at least against the flamers.