Depends on what seats are available
It depends on what seats are available and how much you like direct aisle access without someone crawling over you. The EWR flight middle seats offer direct aisle access and the bulkhead seats are particularly comfortable for a larger foot well. The ORD 747 UD does not offer direct aisle access but I believe are superior seats to the non bulkhead non middle seats on the CO 777.
So my advice look at the seat chart before making a decision.