I really like Rhun. The entire aesthetic of the faction, the obvious eastern influences, and just the region they live in general is all pretty cool. Rhun may look ugly to people due to the yellow grass, but I really enjoy that grass color for some reason; especially in the pine forests. And obviously: the Golden Easterling armor is badass.
When I play as one of the "evil" men factions, I always roleplay as one that has a decent heart, and would rather serve his people and avoid any possible interaction with the Dark Lord and the orcs, if possible. Although, if I do have to cooperate with Mordor, I will use the Olog-hai in my army for sure. ;)