The only difference is the extent of politeness. for example, former one gives me the feeling of like... very strict formality. On the other hand, the latter one might be used in between the elder(speaker) and younger(listener) in business.

not much difference between those two sentenses. just that '오신지’ is more formal and with respect than '온지’. However, both sentenses have '니까?’ at the end of sentense that still have the feeling of respect anyway.