Direct Rental versus Brokers
Ibercar and Al Andalus are direct rental companies.
The rest are “brokers” and negotiate deals with all the actual rental companies and offer some great savings rather than going direct.
They offer competitive prices, but it is worth trying them all, including the direct rental companies, as one may have offers on and can be cheaper than the others.
Personal Car Hire Insurance
Most of the rental companies listed above now offer extra insurance for damaged wheels, which has been a major problem in Spain over the last few years as people are taking cars off-road. Also check out whether glass is covered.
It may also be worth purchasing your own insurance before setting off for Spain.