To be honest, all three dramas disappointed me in one point or the other. However, the one I'm less upset about is probably The Master's Sun.
I have not read the whole thread to avoid any spoilers. You Who Came From the Stars was my absolute favorite drama that I've seen. I felt like it had a bit for everyone. Comedy, suspense, thriller, romance and it did all of them fairly well. Hearing these other 2 dramas being compared to YWCFTS has me intrigued. Which one would be the closest? Master's Sun or I Hear Your Voice?
Out of the 3 dramas my favourite is The Master's Sun. I loved that there was a little bit of everything in there. Horror, romance and Comedy. I loved the actors and the story was perfect. I actually wouldn't mind watching this over and over again! My least favourite would defo have to be YWCFTS. Personally I didn't like it. I found it a little dragging at times and so I was glad to have finished it!! I hear your voice was a great drama. I did enjoy it but I loved the court scenes!
Master' sun is quite good and have momentum of rom-com until the end but it lacks intense/climax part. I hear your voice is really interesting in early episode but it peak too early at half of story. then, after lee jong suk missing, i was hoping for something mysterious and more interesting story, however, what I get is a boring and disappointing 2nd half of drama. You who came from the stars also interesting in1st half of story but decline in 2nd half. The episode should just be reduced to16 to make it better and not draggy. So, I think master sun is better for overall.
The Master's Sun lost me around episode 13 or 14, everything after that was frustratingly disappointing. I was really enjoying the show and several of the "twists" really turned me off. I couldn't stand the repetitive soundtrack in You Who Came From the Stars (I thought it was bad enough to distract from the emotional scenes) but I loved everything else about it. If we went by ratings, I'd pick I Hear Your Voice over the other two, but YWCFTS and IHYV are very close. 

Jeon Ji Hyeon had my favorite female role of the three and I think So Ji Sub had the best male role of the three. 
I think for me I Hear Your Voice was my favorite. Actually I haven't finished You Who Came From the Stars yet. I'm like two episodes away. For me its not so addicting and I just haven't felt the need to watch those episodes yet. I'm not saying it's a bad drama, but for me it just doesn't have that need-to-watch pull. 
Although I love dramas, more and more as of late I'm very skeptical. I'm all about how realistic the actions and emotions of the characters are. So when I find myself constantly being like "Who the heck would do that?" "That doesn't make sense" "Why are they acting like this??" I get really, really frustrated. I don't like when writers make characters do certain things to add to the impact of the story, rather than what the character would actually do.

That being said, I experienced a lot of those "Wtf, why?" moments in YWCFTS. Although, there are many hilarious and enjoyable parts.

I really like the message in IHYV, and I feel like the character development and character personalities were consistent and enjoyable. No huge personality changes suddenly, and the motives were all understandable and believable.

There was a lot of hype for Masters Sun before I watched it because so many people I knew were watching it, so that might be part of the reason I have a sort of 'non-excitable' opinion about that drama. I remember really loving it in the beginning. And I think there was TONS AND TONS of potential. However, I think the character growth particularly for the main female actress was way too forced and not at all gradual.I love the original chemistry and both the actors, but I feel like a lot of the problem was with the with the writers. I think the direction of the story was poorly planned. And the mood of the drama changed so quickly. It was more episode-by-episode story based with a very creepy mood (which I loved) in the beginning, and then It just sort of all of a sudden changed to a focus on only the main characters as if somehow all these crazy incidents that seemed so prevelant before just stopped happening to her. And she'd been dealing with ghosts for her whole life, and in the short time that she knew So Ji Sub her attitude towards the ghost seemed to drastically change. Also, the ending felt very forced. I do like this drama, but I think It could've been a million times better. So much potential. Seriously.
master's sun is my favourite one :)