I don't think either is more correct than the other. However, there is one thing I'd like to mention - would on its own needs to be used with a time reference, while used to doesn't:
I used to (not would) smoke.
I used to/would smoke when I was in my early twenties. (when I was in my twenties introduces a time reference)
One more thing - would never goes with verbs denoting a state.
Student or Learner