Not quite a deal-breaker, but a big enough deal that I will think carefully after my invite shows up (if it ever shows up). OTOH, the pricing model represents something like $30 or more a month cheaper than what I'm currently paying.
I wonder if there are any phone number parking services - I'd pay a modest monthly fee to hook my old number up to a personalized "this number has changed, please call XYZ" and an SMS autoresponder with similar information.