Hi Shep,
I took the plunge and got the upgrade to full Breverb because I wanted the additional algorithms and presets.
It should be noted however that you cannot use full Breverb in ProChannel unless you place it into an FX Chain. But I'm happy with that myself.
As for whether the upgrade is value for money, I'm afraid I can't answer that because I'm not a power user as such. To me, it sounds great, but so does Sonitus Reverb still. I'm easily impressed I suppose.