People seem to either love or hate him, but I'm in the middle. He's the most complicated person on the show, which makes him interesting to watch. I loved watching him pine after Christian. Without Polo, we wouldn't have the amazing threesomes with him/Carla/Christian. I could tell from the first episode that something was different about him-- he's SO repressed, it's insane. He loves Carla and Christian, but Carla/Christian are even harder to read. It's such a unique relationship.
Apart from the fact that he committed MURDER because he completely overreacted to one comment that Marina said, he was already slowly going off the deep end as each episode went on. I wonder if his issues come from his repressed sexuality, or if there's something else that made him freak out the way he did.
I'm not in love with him as a character, but his storyline is cool. I also do think he's an amazing friend to Ander/Guzman and that's neat to see. And, ugh, him/Carla/Christian are just so intense and sexy. LOVE!