I am partial to the former. Granted, I know the idiom originated as the later, but I think both in spoken American English are nearly identical and as an expression I think it is subjective. I say this with vindication because there are examples of swapping and for in and in for and in many parts of english phrases:
Puss in Boots v.s. Puss and Boots
Day in Day Out v.s. Day and Day Out
Down in Dirty v.s. Down and Dirty
Language is constantly changing and this may too be a change as thee to you once was centuries ago.