I really like those tutors explicitly, because they are efficient, but card disadvantage. So they are really not so good when you just search for a kill or counter spell or some random 5-drop. They are, however, cheap and splashable cards to search for important build arounds, so having them in the cube helps more niche decks to work. I wouldn't run
Demonic Tutor for example, but tutoring to the top seems just fair to me.
Drake Haven and
Wildfire decks just don't really work out with their key card on the bottom.
Speaking of fun, deckshaping cards. Does anyone run this one? It is my favorite render I did so far, so I wanted to share it with you guys