Hi, I can only speak from experience, I have used FIREFLY, (never again) they ripped me off, gave me to upgrade, apparently for no extra cost because the car I booked was not available, but then charged my card after I returned to the uk, after a lengthy battle, I gave up because I was getting nowhere. GOLD CAR/INTER RENT (never again) Booked through do you spain, then they said I need this insurance and I had a fueling up service of some kind, just made up all sorts of rubbish. anyway, now I always use CENTAURO there is a free shuttle bus to the depot, Never had an issue with them.
Stuart