Whichever helps me win in the situation I am currently in. Since I don't currently need to create more advanced physics formulas, and they have the same dollar value otherwise it doesn't make much difference.

If I believe in collapse rather than decoherence is Inspector Darwin going to come and declare me bankrupt?

In fact worrying about the difference is a negative point for me anyway, I should be doing other things and devoting time, memory and processing power to this, reduces the amount I have to apply to my problems.