sql server datetime vs datetime2
The MSDN documentation for datetime recommends using datetime2. Here is their recommendation:
Use the time, date, datetime2 and datetimeoffset data types for new work. These types align with the SQL Standard. They are more portable. time, datetime2 and datetimeoffset provide more seconds precision. datetimeoffset provides time zone support for globally deployed applications.
datetime2 has larger date range, a larger default fractional precision, and optional user-specified precision. Also depending on the user-specified precision it may use less storage.