The only ones I've tried were the Mantequillas when they first came out when only the head of the cigar had the maduro wrapper. Didn't really notice any difference other than getting a little of a maduro flavor because of holding it in my mouth.
Reviews that I have read elsewhere describes a richness at the beginning of the cigar and then when it burns past the maduro on the foot it changes.
IMHO it seems to be a gimmick to boost sales.