Biggest difference in riding experience?

absolutely without a second thought.....a rear hub motor.
Then, tires/touchpoints/wheels/weight shaving

touchpoints would include the software as well as the hardware. Expensive shorts, shoes, gloves to match the perfect saddle, pedals, handlebars.

and the latest helmet, because everyone would stare. That would be a big change over being ignored, as are most cyclists on the road.