The biggest perk for me is the faster earnings for free days. There is not another Executive Selection area that makes Exec Elite better than regular Exec.

The guaranteed car is probably worthwhile, but I have not had to use it yet. I am sure that I will sometime, though.

As for your comments about Exec Selection vs. regular Emerald Aisle lots...
I find it depends on what my interests are for that trip. The Exec Selection lot includes Full Size or above. That means that it excludes some nice mid-size cars and sometimes only includes "or above" SUVs that I usually don't like running up my gas bill.

I have come to like the intermediate G6, and these won't be found on the Exec Selection area if they follow their rules of populating this part of the lot. Unfortunately, this means that all the regular customers have the same chance of getting a G6 as I do as an Exec Elite.

At some locations, I have found it worth asking for what I want if I don't see it in the Exec Selection area. The higher level can give you some extra pull in being able to request specific car types.