I guess it depends on whether you'd rather be mostly invulnerable, or able to regenerate anything. I think I'd rather have the latter, since every Logia seems to have some material/element that hurts them(also Haki and Seastone). Whereas Marco can probably just heal any injury as long as he's not in contact with seastone.
How is "healing any injury as long as he's not in contact with seastone" any different from a Logia? There are Logia out there with scars and stuff. For example, Smoker got a scar on his chest in the time between Alabasta, and when he was shown after Ennies Lobby.