It's so hard to choose since they are some of this years strongest pop albums, but I feel like Bangerz has more variety and is more versatile and diverse in terms of content and is abit more edgy provocative and risque, Stars Dance is alittle safe.
Stars Dance has no personality imo. It's just beats thrown together trying to make an album that would've succeeded a few years ago. It's boring and generic and besides Undercover and Save The Day it's all forgotten already.
Bangerz is new and you can clearly see that Miley worked hard on it and tried to do something new.
BRAZZERZ doesn't have too many standouts, the best songs on SD > the best songs on it. SD is shorter too and that is ALWAYS a good thing with albums like these.