I'll declare from the outset that fantasy films aren't really my taste so Seventh Son, an 'epic fantasy' was always going to struggle to please me.
But to my mind even if you like fantasy, you won't like this pile of excrement. Honestly, I just found it a total bore.
It stars Jeff Bridges and Julianne Moore so I guess I hoped that even though it wasn't really my genre that it would still be ok. I mean, Julianne Moore just won the Oscar for best actress for crying out loud! Alas, she is let down by a terrible script. And as for Jeff Bridges, his character speaks like he has a mouth full of marbles, with an affectation fit for a leading man in a suburban theatre company Shakespeare production. (The kind of guy who can't quite work out why he isn't starring opposite Cate Blanchett in an Melbourne Theatre Company production... you know the type.)
Anyway, give this one a wide berth I reckon. DVD/digital at home, at best.
This review of it in Variety is pretty funny, if you're interested in reading more about the story and what a proper critic thinks. (eg. "Here, it’s downright uncomfortable to watch an actor as good as Bridges fumbling lame one-liners")
Trailer here.