I think the only real danger is the potential for developing a speech impediment from all the tongue twister words.
@Lurker brought up a good point regarding Paul Foster Case in a recent thread regarding the Shem. I recall some debates around his perspective of Enochian being fatally dangerous because he lost a dear friend who used it to some horrible disease. He blamed the magic, though later I read his perspective was rooted in the notion that the system is incomplete and unexplored.
Donald Tyson seemed to me be heavily fixated on the apocalyptic aspects of Enochian, but I recall at some point he walked that back at some point and said he meant "personal apocalypse" as in a self-realization type thing.
I have used Enochian for years as part of my work and, aside from the occasional freak weather even coinciding with the use of certain calls, I don't think it is any more dangerous than the Simon Necronomicon, and a lot of people think that's just a sham.
Also, I think the spirits I have interacted with are quite witty and have a great sense of humor.