Now, concerning the actors, I knew just Lee Min Ki and L at first. I mean seriously, Min Ki is really cool and he's just so adorable in this show (and in general) and Kim Myung Soo is just...Infinite :D I love the band so yeah...I'm a fan of L's and I went immediately to check up the drama so yes, these two are the reason I started Shut Up Flower Boy Band in the first place. However, there are other actors who caught my attention more throughout the series. One of them is Sung Joon, actor I knew from Lie to Me and I was really surprised to see the change in characters. Ji Hyuk is that kind of leader who's torn between his own selfish dreams, his best friend's wishes before he died and the band's dreams. That's a lot. Anyway, his skills are good. He kind of annoyed me at some parts but it was alright overall. Regarding Lee Hyun Jae, he's very good looking:D Sorry I couldn't stop myself. He looks much more caucasian than asian. His eyes are big and he just reminded me so much of some good, old bands I used to listen when I was young. His character, Jang Do Il, is the drummer and there's some good skill there. I love how his character ends up to choose a completely different path than expected. The complete cutie of this whole drama is Kim Min Seok. He's adorable and his character's relationship with Yoo Min Kyu's reminds me so much of the whole EunHae thing. Seriouly, they are such good friends and act so close and it doesn't look gay or things like that. It's a normal brotherly friendship. Both actors have done a good job.
Now, of course the plot has been a little dragged on and I thought it got a little too much on some episodes. Some reactions have been a little overreacted by the actors and it was obvious some of them didn't feel their characters as deep as they should have. As a soon-to-be director, I would say it was a medium drama and the screenwriter should have improvised more and at a more psychological level so the plot would get more interesting but it's still worthy to watch.
I know I ignored some details in what I wrote above but where would it be the interest if I woudl have just wrote everything here? Watch it and enjoy it :)