I've noticed some drops but no tearing. Its a great experience and I recommend it. I'm sure from will patch it up to improve performance too.
I gave had the game crash on me like 4 times now though... don't know if that's uniform across all versions.
I find the Xbox version plenty smooth, but likewise I gave seen a muddy frame rate here or there. Nothing like the hyperbole going on about the XOne frame rate in the DF thread. Knock on wood. No crashes yet.
I don't like the controller for a souls game like I liked the PS4 controller for Bloodborne ... But dammit, achievements are worth more to me than trophies.