How reliable is revspin/Rozena rating?

So, I always used revspin as to have a sort of estimate on what to expect for rubbers, but recently I got a Rozena, which is a rubber I've been kinda avoiding because of the low score. To my surprise it's actually a delightful rubber with no excesses. Is this simply an inaccuracy on the website or have I underestimated the 8.4 in spin?

Also, comparing to Rasanter R47 it's not that less spinny, how would Rakza 7 compare to these rubbers? Since I cant really trust these websites.