After watching a few episodes of each, I can tell that my favorite is also Top Knife. Even if you're not into medical dramas, I think it's good because it deals more with social or psychological problems caused by brain damages. Furthermore, the doctors and their private lives are also interesting to follow.
My second favorite is Kotaki Brothers. It's funny, different, the actors are great and I think it's a good mirror of what the Japanese society can be sometimes so it's easy to rely on the characters of this drama.
My third favorite is Theseus no fune. The first episode was quite disconcerting and even disappointing but the second one was quite interesting and now I'm really hooked.
I'm disappointed by Kirin ga kuru. First, the colors are too bright and you didn't have the feeling to be in a period drama. Second, the cast is not good, especially the feminine cast. When will NHK stop using young people that are famous for their faces more than their acting abilities? People who are into taiga dramas don't care about idols and stuff, they want good acting even if the actor or actress is not "beautiful".