Yes; that out-of-pitch Dona singing is pretty awful. However, beginning around '76, I think (I could be mistaken) her singing was much more on key and I enjoy her contributions to the band, from that point on.
"Personally, I’m excited from time to time to see a recording that has undergone a process of remastering but in the end, the price tag is a very big factor in whether I’ll pull the trigger"
Yes. Same here, but if I'm honest with myself, most of the remastered versions of favorite recordings I end up buying are at best, moderately better (if at all -- many are simply different) compared to original versions. It's rare that I encounter a remaster that offers a dramatic improvement. The fact that this does occur, from time to time, is what keeps me buying them. Of course, now that MoFi is (for me), out of consideration, there are fewer to choose from. I will continue to keep an eye out for Analog Productions releases.
" I do like many of the Rhino remasters but as a whole, don’t hold the opinion that they reach the same level of refinement as some MOFI and most Analogue Productions do."
Perhaps my system isn't capable of revealing such "refinement". . . or else, we are listening for/prioritizing, other aspects of the sonic presentation.