Best Actresses based on acting ability

Moon Chae Won, Han Ye Ri (she's such an underrated actress), Soo Ae, Kim Mi Kyung, Kim So-Hyun, Kim Yoo Jung

@Hanah, I've only seen half of W - Two Worlds - I plan to finish it I just got caught up with other things.  Glad to be of service ma'am :D

I personally think that Park Bo Young is the best actress in her 20s, she's so versatile. 
Kang Sora and Moon Chae Won are some of my favourites, they excel in strong female characters. 
For comedic acting, Kim SeulGi, Gong Hyo Jin and Kim Mi Kyung hands down. 
EunJi is my favourite Actressdol and Seo Hyun Jin was my biggest discovery for 2016.
Jang Nara and Han Hyo Joo are usually a hit or miss for me.
Han Yeri's great at heavy roles, Choi Ji Woo's great at melo.
I did use to like Han Groo, but she had only one hit project (Marriage not dating) and nothing to follow up so it's kind of hard to judge her acting based on that one project
My profile's full of actresses, there's too many that I love

Ra Mi Ran and Han Ye ri!

Lee Bo Young, Park Min Young, Ha Ji Won and Moon Chae Won

In general I praise teen actress Kim Sohyun the most. I think she can beat many adult actresses.

Also, Han Hyojoo in Love, Lies
Son Yejin in The Last Princess

Gotta mention these two in these particular movies because I either haven't seen their other works or their other works didn't boost their acting.

Park Bo Young and Kim So Hyun

Gong Hyo Jin

Han Hyo Joo

Kim Sohyun on the way up as well. Hope she gets better roles next time, She does loook good in Saeguks lol