hi Renting a car in Spain and I noticed the rental price for the month was about $90 less at Enterprise vs. Emerald but was wondering if I stick with Enterprise Im not sure id get the Executive Elite upgrade that I would like to get at as a National any thoughts?

also does anyone have an experience rented at Enterprise/National in madrid airport, I was wondering if I were to get an upgrade from Compact Elite Suv (XC40 or similar) what should I expect?