Whelp..if you sparr with 4 oz, might well go bare knuckles.... Anyways, of course genuine leather is always better than synthetic. But for something like mma fight gloves, which imo should rarely be used unless in actual fighting (in which most of the time provide their own gloves) I wouldn't mind to go with their synthetic. But if you are going hard with fight gloves all week everyday then get the genuine leather.