I'd like to state what makes a good crosshair, and what should be avoided when creating one:
A crosshair should be crisp, clear, and it should minimally obscure your view of the target. An overly complex crosshair is not better than a simple one, as you are distracted more by the crosshair, rather than the target. Symmetry is an important factor, as well as balancing vertical features with horizontal ones.

This crosshair is somewhat complex. Notice how the bars and the center ring could obscure your view of a target.

This one is simplified, and provides an easier view of the target. The bars and the middle ring have been removed. Even the outer ring could be removed for further target clarity.

A green dot differs from the original black dot, which may or may not favor someone depending on the situation. This could come in handy in situations where you need to see the point of the crosshair if the environment is dark.
In my opinion, the
best crosshair is the default one, but I do believe that people should feel free to post their ideas and creations. For those of you with less confidence in your creations, I recommend that you do not become defensive against criticism, constructive or caustic. If it does not bear any information that could aid you improve your work, then let it be dismissed, and not rebutted to yield nothing.