Coming from someone who still uses their 2013 11" MBA 4Gb/256 Gb SSD, defo get the machine w/ 8Gb RAM as the 4Gb RAM is the most limiting aspect.
I still enjoy the screen, keyboard, weight and form factor, my battery is still 80% health (and I upgraded the SSD w/ an OEM takeout years ago)...its just the 4Gb RAM that has me wishing Apple still made something similar in form factor!