I hope I am not too late, I am currently watching it on dramacool. The subs seem fine to me. Have a try.
I did start watching and felt the subs were manageable. But, I dropped the drama as I didn't like it much. Now that you mentioned,I went back and saw that the episodes about 3 months back. Sorry, for giving the wrong information
The Long balladJoy of lifeLegend of feiAre my favorite historical drama
Hwarang, The Scholar who walks the night, 110 days my prince, Chicago typewriter, Buzzer beat, Perfect and casual, are some of the ones which I rated above 9.