Male characters in OP are generally "just" good looking kinda like the girls (except a few exceptions like Hancock who has a very distinctive Top 1 look
), so you'd find that people have very varied opinions on who is the best looking male character in OP, some would say Lucci for example, some will say Zoro, some will say Sanji, some would say Ace etc. and it'd often come down to how much you like the characters, their style, how badass u think they are etc, so at the end of the day isn't necessarily about how distinctively good looking the character is facially. Also, handsome male characters in OP usually have a more "mature" look but Momo is slightly different from the norm in that he has a more youthful look to his design so he stands out even in comparison to all the characters I mentioned above. Then add stuff like that dope kimono, (i.e. his style) that wavy long hair and how badass he looks and you have a clear winner ^^.
Just hope he doesn't opt for the generic Samurai style look and shave the front of his head
but then again Oden didn't shave his head so I think we can rest easy on that ^^