the one drawback from the pnm side is that they may end up going back to a sorority they did not want to revisit again. the up side is that their opinion of the sorority they did not want to revisit may change with a 2nd look.
Priority ranking is really nice from the perspective that a pnm takes a second look at a chapter she may not have thought highly of originally. I suppose it could be the same if you aren't invited back to the one chapter that you were really gunning for and then end up looking at the others more closely, but it seems like that would be less likely to happen with accept/regret.