Our family has done both (different years). You have to be at least 8 years old for the sea lion encounter, so my daughter (then 6) and I observed while my husband and son (10 at the time). I don't think one was better than the other. Both were fun. The biggest difference from a pictures standpoint is that I saw people wearing Go Pro cameras during the dolphin encounter, but you are not allowed to bring any cameras to the sea lion encounter (because they think they are toys and may go after them). Would you rather be kissed by a sea lion or a dolphin?