There is a world of difference between both the workload and type of patients between Neurology and Neurosurgery.
It might not necessarily be true for everyone but I felt that the desire to physically intervene (surgery) would be a major determinant as to whether to pick Neurology or Neurosurgery. And of course the lifestyle.
In Neurology you would expect occasional bursts of busy, and spend half the time in training whereas in Neurosurgery you would expect to never go home.