Many yuri series heavily features the drama caused by homophobia and the characters' fear of rejection. These two are not like that. Instead they focus on relationship fluff and are mainly adorable.
Fu~fu is a slice-of-life manga without any real overarching plot, while Kotonoha no Miko to Kotodama no Mahou to contains some magical problems for the characters to overcome. However, both are love stories which do not focus on relationship drama. (Though KtMtKnMt does contain some dramatic moments, those are caused by outside forces.)
If you liked one, you'll probably enjoy the other.