If your students can use the traditional algorithm correctly and understand why it works, then I suggest allowing them to use it. The key though is that they need to understand why it works. Nontraditional algorithms can help students make this connection. There is nothing wrong with the traditional algorithm. The problem is that many students do not understand why it works and therfore make mistakes.
The goal should be efficiency and fluency. Depending on the size of the numbers, students should be able to choose different methods for solving problems.
