I will admit, I’ve never really read or watched Constantine much (I know, I know, shame on me) However, I will take into account that I shouldn’t count him off as weak based on my own ignorance, so I won’t, and if I were living in the DC Universe, I would think trying to get to his level in the mystic arts is harder than it looks (I mean, I already know that IRL but still), so it’s best to assume that he’s a pretty powerful character and should not be underestimated by any means. Zatanna, on the other hand, I’m familiar with certain versions of her, such as Young Justice, Batman TAS, and when she appeared in the Gotham City Sirens comics, but I wouldn’t know everything that is more explained in her comics, or stories that have her play an important role. I will say, that just the idea of physically talking backwards is hard for me to think about, because while saying just one word backwards may not be bad (especially if you are reading it on paper backwards), but Zatanna has to say an entire sentence, even sometimes on the spot if something happens. Zatanna has to practice these spells (which she stated in the Young Justice show) as would anyone who practices the mystic arts. As much as I love to overthink and analyze before making a decision, I have to vote on Zee for this one, because I’m more familiar with her, but even I can’t deny the fact that these two characters are very powerful with magic, even if one is talking backwards, and the other isn’t. And this doesn’t even include the emotional side of things either, this little comment analysis is simply based on skillset and my limits on character information.