I think it's probably worth a call to find out if the pricing discount applies on the Club card. I still have my Presidential Plus card under that scheme and get tremendous value out of it. The discount that comes with Avis's President's Club is fantastic--it's usually enough to make it cheaper than the deeply discounted guys like Enterprise. (I doubt it would hold a candle to true employee discounts though.)

Also, keep in mind that if you can make 25,000 miles in a calendar year, you'll get priority security and priority boarding anyway, so if you're transitioning all of your travel to United, this may just be a stop-gap measure until then.