For me, he's kind of arrogant.
Maybe he's a great guy, but I haven't seen it yet. I don't hate him, just sort of doubtful about him.
A lot of people don't like him, at least from his singles. More because he fits into this 'vulture' category, and people think he's a 'pusher' or a 'grinder'. I think those that do can partly be accused of tennis stereotyping. It seems that every new player from Spain these days is labelled in such a manner. I'm not saying he has the most interesting style in the world, but he wouldn't be such a great doubles player if he didn't have talent in the forecourt.
He can lose his temper very occasionally, and perhaps one could say he struts around in an arrogant manner. I think he's great, though. One of my absolute favourite players.