MAPFRE is one of the biggest insurers in Spain.
You see a lot of offices for them in the main cities. Parador have been pushing them quite a lot as well - we've had a fair few leaflets.
They price very competitivley but we found that they didn't respond to enquiries. As that was before they got the money off you it didn't seem to bode well for any claims / enquiries you may have after you take a policy out.
HTH