CAN J1939 or OBD-II Preferred for Digital Gauges?

[cray54]

I'm looking to put a digital gauge setup on a 98 Cummins 24v ISB engine (swapped into a 79 F250). I'm wondering if there is a reason to choose to read data from the CAN bus or the OBD-II port.

Is either faster or more accurate? CAN systems tend to be more expensive, but I'm interested if the expense is worth it.

Thanks,
Chris