I love the ESS and it was one of the reasons I bought a Cherokee. It makes a noticeable difference in gas mileage when driving in traffic. Plus I like how quiet it is when I stop. When I drive my Challenger R/T and pull up to a light, I think "Hmm, why's the engine still running?", then I remember which car I'm in.
I truly don't understand why some people want to waste gas and not save the money. I've seen some on the forums say that where they drive they don't have to stop much and therefore don't want the ESS. Well, if you don't have to stop much, it shouldn't be bothering you much, either! And as far as wanting 'control' over the vehicle, why aren't you driving a stick shift car?
I have 11,000+ miles on my Cherokee and the ESS has worked extremely well. A very easy learning curve, too.
2015 Cherokee Limited - Ordered 10/21 and built 11/14. Took delivery on 11/21/14 - Deep Cherry, V6, ADII, all the tech stuff and options except a sunroof, CD player, subwoofer and charging pad.