I rented from DEN 9/2 - 6, picked up at 6pm (Wednesday).
Premier: a few basic BMW 330i and Audi Q3 with ~$30/day upgrade fee
Executive: Pretty slim pickings. Ended up with a Nissan Armada SL (17k miles). A ton of Dodge Caravans.
Standard: Mainly Ford Edges and Jeep Cherokees. Lot of Nissan sedans.
Also noticed a few pick ups.