The upgrade to electronic shifting is a bit easier with SRAM. The shifters, like the Ultegra and Durace Di2 shifters are wireless. Unlike the Shimano systems, the SRAM front and rear derailers have their own batteries, so no wiring needed between components. With Shimano, you would have a battery inside the seat post, then 2 separate wires, one to the front derailer and one to the rear. That wiring needs openings in the frame in order for the e-tube connector to get to the derailers. You might find yourself drilling holes in the frame for the wiring. Thus SRAM is simpler, if you are OK with the shift system, which is not how Shimano works.