I would recommend you favour the digital interface over the analogue one.
You do not mention what distance the MB7092 analogue output will be travelling to reach your Arduino but it can pick up noise on the way. Another consideration is that the ADC will have a variety of conversion errors that will bring some inaccuracy into the ADC output.
On a brief examination, I cannot see if the sensor (a) starts with an analogue measurement internally then also converts it to digital with an internal ADC or (b) starts with a digital measurement internally and also converts it to analogue internally using a DAC. I would venture that it probably does (b).
If it is (b), then using the analogue output would mean the MB7092 reading going from its DAC to your ADC, increasing the errors between its internal digital value and yours.
The digital signal is much more resilient to noise so it travels better. It uses two wires (RXD and GND) just like the analogue input would have to. And it may involve fewer DAC/ADC conversions and therefore be more accurate.