Ouken seems to get way more fanart from my perspective but I see more people relating to Despa as a person. Not that it was anything bad but I feel that most of his fans like Ouken for fetish reasons and the general sexiness, whereas is Despa loved for his personality.
Desha is kind of both. Personally I would even say that Despa has the most interesting mindset of these three, but it's maybe a bit unfair to say that since he had the most screen time so far and nobody knows what kind of development will start with Desha and Ouken with in their new roles. I just hope the manga will have some subplot for Despa as well.