Today's MG paper is very good.
I target Ilford Galerie Graded FB paper and use MGIV FB paper only when I have to, usually when I need grades 3 1/2 to 4.
I don't have any negatives that require 00 grade, so haven't seen that curve anomaly. If I did have some very long scale negs I would be very interested in printing them on Platinum/Palladium.
Other than slight surface texture difference and some difference in the way Selenium toner takes... I find the results I get from MGIV indistinguishable from the results I get with Galerie.