While You Were Sleeping or I Hear Your Voice?

I hear Your Voice.  better story development. 

I hear your voice is top tier. 

while you were sleeping is the best

 Zoecohen:

It's almost like Lee Jong Suk in While You Were Sleeping is playing the male equivalent of Lee Bo Young's role from I Hear Your Voice, though toned down a bit. I know not all prosecutors can be super righteous and driven by justice and all, but I was still frustrated with I Hear Your Voice for just how long Lee Bo Young's character was an awful person. I don't remember how far I got into that show (because I dropped it), but it was taking her way too long to become a decent person. It's not like I expected her to be perfect because that's really hard, but even just being a decent person seemed a struggle for her for a while. It's a shame because I quite like noona romances, but at a certain point I just couldn't take it anymore haha. For those who preferred I Hear Your Voice, what stood out to you about the show?

The actors/characters felt more genuine and memorable in IHYV, like some situations made me cry more here like with Lee Da Hee and when the courtroom apologized to that man (forgot his name since I watched this a long time ago) Kim Kwang Gyu was the funniest supporting actor here for me while I didn't really care for the supporting characters in WYWS (it looked like they were trying too hard to be funny) other than Kim Won Hae. But I guess younger generations of watchers may prefer the younger actors and more modern cinematography/OSTs of WYWS..

While you were sleeping is one of the strongest and best first episodes in all the kdramas I've watched.

Considering I binge watched I Hear Your Voice in a single weekend and I'm still struggling to finish While You Were Sleeping after a month, I'll have to go with IHYV. 

I never really felt the thrill factor with WYWS because the dreams are sort of the ultimate cheat sheet and watching the same formulaic repetition of dream → problem → solution gets old quickly. The characters are also kinda flat and go from zero to hero with too little effort, so there's no real drive to root for them or sympathize with their journey. Also, no strong SFL to play foil for FL like in IHYV; it's all about ML here. The production very pretty, but that doesn't improve the narrative.

With IHYV it's high stakes from the beginning and the leads make serious mistakes with permanent consequences that heighten the tension. Both ML and FL struggle with knowing what the right thing is (let alone doing the right thing) and it makes their journey more personal and intense. The acting is also way better; both Lee Bo Young and Lee Jong Suk were nominated for Baeksang awards. The major downside is it's old and it looks old, but that's never stopped me from watching great TV.

More personally WYWS's romance was just meh for me. It developed too quickly out of nowhere and I never really felt like the leads had anything in common beyond the dreams and their childhood connection. With IHYV I felt the story did a great job of showing why the leads fell in love and how they were uniquely suited for each other despite their differences.

 Miradaisy:

Definitely while you where sleeping

I have to agree with that commenter who said I hear your voice is hardly bearable at a certain point and I dropped it.

Also I have to strongly disagree with the commenter who said the characters in while you were sleeping where flat and one dimensional and go from zero to hero. Did we watch the same drama? 

We did watch the same drama but the difference is I'm comparing the story and characters to IHYV which you dropped before the major plot points happen. No shade, but it's hard to pro/con two dramas if you haven't actually seen one and most people in this thread who've watched both agree that IHYV has the better story. It's one of the most popular and highest rated classic dramas for a reason.

If you enjoy episodic format over complex plots or don't like the production style and slower pace of classic dramas WYWS is probably more appealing, but you're missing out imo. And considering in WYWS FL gets over her fear about changing the future and her death and ML goes from clueless rookie to rescuing everyone all in first six episodes I stick by the zero to hero call out.