My advice in 2017 has changed from 5-10 years ago. Now, my advice is simply to sign up for all of the "expedited renter" programs and then rent from the cheapest one.

Bottom line: none of them are as good as they used to be. There are fewer XM-actually-working cars, more high-mileage cars, deteriorating customer service as a norm, worse cars by category (e.g. a 2007 compact is a 2017 midsize), and greater difficulties getting problems resolved.

I have probably 500 lifetime Hertz rentals, mostly from 1995 to 2015. The entire experience is vastly WORSE than it once was, when Hertz was truly the gold standard among rental car agencies.

If I was a weekly road warrior with company-paid rentals, I'd probably align with National. They've deteriorated less than the others, and in some locations still run a pretty nice Exec Aisle. That then puts your neighborhood rentals with Enterprise, who aren't my favorite but at least they're everywhere.

Most of my personal rentals in the past 5 years have been Dollar or Alamo. I can usually work the coupons and promos and get them a lot cheaper than Hertz or National. Their expedited-renter programs are sufficient. The single most important benefit with a program is not having to stand in line, and both work well enough for that.

If you manage to run into the various annual promos like 1-2-FREE (National) or the similar Hertz one, great. But don't overpay for them. Figure out what Hertz points or National free days are worth to you and don't overpay for the basic programs either.