For car rental in Ibiza, I have found that local Car Rental company www.motoluis.com. the best for overall service and reliability. They have cars parked at the Airport (100m from arrivals) and their check in and drop off is fast and easy. Fuel policy is full tank going out and leave back full. They offer a 24 hour service (€10 fee outside office hours) and have no hidden charges or tricks, standard insurance is included.
They will also deliver cars to hotels anywhere on the Island. Its a family run buisness since 1956 with a professional reputation and I have dealt with them for over 15 years now. Their prices work out better than most and as a special bonus, if you mention the Dannykay blog, you will receive a 10% discount all season long. Have a look at the Moto Luis website, choose your vehicle and then just contact [email protected] to receive the exclusive discount. Moto Luis also rent out Mopeds and bikes and will apply the blog discount to bike rentals also.
N.B: The above special 10% discount is not valid in conjunction with other promotions, discounts or vouchers.