Have you considered the tax implication?

I think that rolling 401K to a rollover IRA has no tax consequence, you have to pay the tax when you withdraw the money.  If you convert it to Roth IRA, you have to pay the tax now.  Flip side, Roth IRA withdraw will be tax free, Then the question becomes whether paying now or not.  If I were you, I will delay paying the tax as long as I can.