Just had a look through with the CDs at YBM, Cheonjae (2 different ones) and Daegyo. My school uses Daegyo and after comparing them, I think Daegyo is best for phonics but content wise they seem totally similar (except the one with the chapter "TA-DA! I have a pencil" because we're not training magicians).

YBM's phonic section doesn't really make sense to me because you don't study similar phonic sounds together b/p, c/g, r/l but just pick letters at random while the Cheonjae books skip from the alphabet directly into random letter and even compound phonics (they also repeat the same phonics in the book "oo" and "d", which is unnecessary).
My students would get confused by that, I think.

I'm hoping my coteach chooses Daegyo again but apparently one of the Cheonjae books is most popular because of teacher's resources so I think she might go with that.

Choosing a book should not be based solely on the student's textbook. We should have access to the CD/DVD and teacher's guides and be given time to look at them. Also, cars should obey stoplights, motorcycles should stay off the sidewalk, and people shouldn't piss in the street. But hey! Welcome to Korea!

I was told to pick the top 3 companies of the 5 we were given and to order them as 1st, 2nd, and 3rd best. As I implied above, I was given no CD, DVD, or teacher's guide. I was given enough time to examine them but now two other teachers are rethinking my choices for whatever reason.

recently i was able to have a brief look at all the books, and I actually liked the Daegyo the best. My opinion is just based on a brief look-over of all of them though, and I wasn't able to examine the teachers' guides or CD-ROMs.

one of my co-teachers who is a veteran English teacher always raves about the Daegyo books too. So I'm sure you made a good decision Summer 

I can't find the link path you described. Where is the link to view the pdf of the textbooks?