actually that regex one, is really a better fit for Programmers.SE because:
1. It's comparing A vs B
2. It's narrowed-down code for a very, very specific problem
3. Invites short answers being either A, B, or C (should be reworded to also ask *why*).
4. The best answer will probably inform the OP about the inner workings of the regex engine being used, and explain how A|B is more efficient than B|A because of XYZ. This is very informative, but it's not a code review.