It took me awhile to finish the first season, bc I'm not a fan of horror movies/TV series. I definitely don't like zombie stuff.
BUT..... I like this one. I love the period setting and the court intrigue. Still not a fan of the zombie part, but I can deal with it. I've watched so many other Korean and Chinese dramas, as well as Japanese animes (half subbed/half dubbed), that I don't get why ppl are so against reading subtitles. Also, to dub it, you would either have to have the entire cast do their lines in English, or deal with the English voice over not always syncing up to the actors speaking natively. The first option would make production take longer. The second is far worse, in my opinion, than reading the subtitles. Then again, I'm a fast reader, so they don't bother me. I'm also sometimes partially deaf, so I use subtitles a lot, anyways.
Overall, good show and can't wait for the 2nd season. Get over your bias or whatever problem you ppl have with subtitles. Some shows are better in their native language.