I've used doyouspain many times in the past and have found them great.  Usually you end up getting the cars from either solmar, auriga crown and more recently goldcars.  Didn't have any problems in the past.  One advantage is that you don't have to pay up front - only on the day you get the car.  Last summer, I couldn't get a car in reus as they were all booked up - I booked in plenty of time this summer with doyouspain - car from goldcar..........Hopefully when I get there.