This is one of my favourite dramas.It has such a great plot and evil nemesis.I have always quite liked the lead but surely one character can't ruin the the whole drama there is more to the story than one guy.
Do you not like the actor or is it the character?
Saying all that though if you have tried it three times already then maybe it just isn't for you.We all have different tastes and I have dramas I've watched and really enjoyed while others have hated.
Maybe try watching the first 5 episodes and if it's still bad give up and watch something else there are plenty of dramas to watch.

I think this drama is highly overrated. I dropped it, but at the insitance of a friend, I picked it back up again. I forced myself to complete it. I think I rated it a 6 or 7. It has a few moments but for the most part I found it draggy and boring. I have seen worse dramas, though.

Before this the only dramas I watched with this lead actor (Lee Seung Gi) were My Girlfriend is a Gumiho and Shining Inheritance. It was not that I didn't like him. He played his parts well and the dramas were nice and all. But it was The King2Hearts that made me recognize his skills fully. The first few episodes his character is an ass, as to say. Can't deny it. But while watching you can see him mature step by step. It's worth to watch his developments.

If you trully don't like the actor and all, don't try it. I, for myself, can't get through a drama and fully enjoy it if I don't like the actors. May the drama itself be a masterpiece and all. It just doesn't work for me in that case.

Sick with it, he grows up and as I have written. This is a rare dram that gets better a it goes on! I promise, everything with get so much better.