For the last 4 or 5 years I have booked rental cars on the DL website with Alamo as my preferred vendor. Have always received excellent service from them in both normal and non-normal situations. Usually they are one of better priced options too. I always earn a base rate of SkyMiles plus daily bonus.

Very rarely use Hertz anymore. They are usually priced higher than anyone else (except Enterprise which is normally insanely high). Hertz has also declined to honor the selected online rate to me numerous times even when producing a confirmation. I have been tempted to try them again as a PM with Delta for their elite benefits, but keep going back to Alamo.

Hotels are a tossup. I really like Hilton, but to my knowledge Delta no longer partners with them (or at least you can no longer double dip and get both hotel points and airline miles).

My new company prefers Marriott, so I just signed up for their Bonvoy program yesterday.