Hot Spring and I guess Caldera (same parent company)gives you a box - others do not. It isn't too much of a big deal. I think I paid about $60 - $100 for a disconnect. The breaker was another cost which either way you would need. Go to Home Depot or Lowes and check the cost out. BTW, I think Sundance can use a 60 AMP service - see how much difference that is from 50 Amp.
Don't let something like that persuade you either way - let the tub and confidence in the dealer be your guide.