i don't onw the mediterranean but i own the caribbean. the larger head of the mediterranean will give you more throw, while the caribbean will be less throw but more balanced between throw & flood.
if you intend to keychain this light, like i do, then the carib might be more comfy than the medit. otoh, some buy the 2AA body for the medit and slide it into a holster, and the medit's larger head makes it more suited for that. also i believe the larger head of the medit might make it easier to operate one handed. the smaller head of hte caribbean makes it difficult to operate one handed.
i bought the carib because i wanted to keychain my light and went for as small as possible. hope this helps =)