Technically there is no difference in sound, nor could there be, the CD inside the packaging is the same Red Book Standard format as a Jewel case or Digipak CD.
This should not be confused with the quality of the mastering, as we all know this varies considerably and is purely a matter of personal preference, so the perceived sound depends upon which remastered version of the CD is used - the people who make the paper-sleeve replicas do not have the ability to produce a new remaster. People who claim paper-sleeve replica's are superior "audiophile" quality will also buy snake oil.
What you are paying for in the increased price is the reproduction packaging so if the original vinyl album had run-of-the-mill packaging then a paper-sleeve replicas will be unimpressive. Personally, I only go for those albums that had impressive packaging to begin with, such as Consequences by Godley & Creme and Pentateuch of Cosmogony by Greenslade (both of which I have), but a paper-sleeve replica of a bog-standard gatefold that didn't even come with a lyric sheet... what's the point of that?
At the end of the day, regardless of what the original packaging is like, what you are getting is a twee novelty item for fans and collectors, not a better product.