I made a 4-day rental car reservation at Payless via Travelocity for Christmas. The total quoted was ~$220.
When I arrived from the airport hotel on Christmas morning, because I was paying with a debit card, Payless wanted to charge an additional $350 deposit (that's $570 total) on the card. I only had $399 on the card but they would not budge on the deposit. They did however offer that Alamo doesn't charge a deposit.
So I walked over to Alamo and was able to get a great car, with no prior reservation, for just $250. Needless to say, Alamo rescued what could have turned into a lousy holiday.
I think the guy who helped me at Alamo was Mike. He did a great job, had a sense of humor, and worked with me to solve the problem at hand. I would definitely use Alamo (at least the Phoenix Sky Harbor one) again. And next time I need a rental car locally, I will try them first.
PS - Alamo lets you choose your own car in the selected category (e.g., Compact) which no other rental car company has ever offered me. It was great because I've been thinking of buying a Nissan Versa and Alamo essentially let me take one for an extended test drive. Awesome!