First the closing company should answer this question and explain the differences however both are for titling purposes and doesn't mean anything on the income tax return ... either way the survivor will get the step up in basis.
What this will affect is how or if the property will need to be probated to remove the decedent's name.
Joint with right of survivorship only requires a death certificate be presented to remove the decedent and perfect the title and is the easiest, quickest & cheapest option.