babies that are exclusively breastfed...

if you give your baby a pacifier, which ones do you use? my baby was given the round green one at the hospital and he has been using that.. but i also had mam pacifiers at home that i originaly wanted him to use.. since he was use to the hospital one i never tried to switch.. i got curious and gave him the mam one today and he liked it and used it. he actually went back and forth between the two, without issues.. but i am wondering if this could mess with his latching on my breast or if one pacifier is better than the other or could he use both? they are completely different nipples on both pacifiers. he is 3 weeks old btw. any response or advice is very much appreciated!