Popeyes has gotten considerably worse in the last 4-5 years imo. Debut chicken sandwich was also of much higher quality than the ones they sell now.
KFC is extremely hit or miss and a lot of their items are ripoffs portion wise. But on a good day, extra crunchy still has an appeal and the seasoning is still solid.
I've had churchs a couple times and both times were extremely bland but juicy.
But most importantly, biscuits.
Popeyes > Churchs >>>> KFC
Since only from below can one better see the heights.
http://i.imgur.com/OhZgm.jpg