I've been renting cars from gemut.com for years, mostly because it's easy, and I know they are a phone call away if I run into a problem. I've only needed airport rental desk help once, but they answered immediately when I called from FRA early morning, which was after midnight on the west coast where they are.
They also advertise they will match a better rate if you find one. I've never tested that before, but this week I received a promo email from AutoEurope about a 15% price drop on fall rentals in Italy. I have an October AutoEurope rental from Florence that I booked through gemut. I didn't even bother doing the math, but forwarded the promo email to Andy and asked "Does this work for me?" Within 24 hours he responded with the 15% reduction in my rate and said the refund will be on my credit card in a few days. I continue to be a happy customer with gemut.