Interesting, I had not seen one outside Japan for a while...
Not sure now about the plinths. Was going to make my own, only because I did not find one with plinth, but if I could get the TB-2000, I would probably take it. It is a pretty bulky/heavy plinth on its own. I don't know if the one with the arms is as good - though if they were the same price, I would go for the one with two arm slots. FWIW, I have never seen replacement armboard slots (though they must exist somewhere).
Not sure now about the plinths. Was going to make my own, only because I did not find one with plinth, but if I could get the TB-2000, I would probably take it. It is a pretty bulky/heavy plinth on its own. I don't know if the one with the arms is as good - though if they were the same price, I would go for the one with two arm slots. FWIW, I have never seen replacement armboard slots (though they must exist somewhere).