Besides the e-start, I think the X will have a spark arrestor, will be California legal exhaust and emmissions (may not matter where you live), 18" rear wheel, o-ring chain, kickstand, larger tank, odometer, head and tail lights, wide ratio transmission.
If you value those things, you would be hard pressed to add even a few of them to the R for only $200.
If you don't care about the e-start and you want extremely light weight in a trail bike, the ulimate would probably be getting the R and spending lots of $ turning it into a X. Or you could get an X and spend lots of $ to put it on a diet. Or just get the one you like the best and ride it.
IMO, Honda should be applauded for giving us the option. And 232 pounds (the X claimed weight) is pretty light for a trail equipped e-start 4 stroke, even if it is only 250cc.