I put my old 500 back up, but only because my 121 sd was damaged by Katrina, everytime I got a strong wind it would move just enough to loose a signal and I was constantly having to repeak it, other than that I would of probably left the sd up
I'm considering the exact same thing with SD 105 vs. D500.
I'm looking at another alternative of running two separate dishes (probably Winegard 30" or Fortec Star models) for 110/119 as I'm fed up with SC rainfade even though I have good signals over 100+ on most transponders. I'm hoping to reduce the rain fade significantly.