The Mobius strip is a … strip. The best approach is to model it with a surface without any thickness. It could be done as a thin solid as in this image, but how thin should it be?
Changing parameters (the thickness) you will get something different. Do you think that this is a Mobius strip too?
Or how about the solid in this last image? It is almost a Mobius strip -just it is completely different.
The lisp is HERE