First, get high coverage. With proper coverage USAA is tops, but only offered to Armed forces. AAA is great for homeowners, (also offers auto, umbrella) because they were only company that paid all claims during fires. Remember there were many complaints against Allstate and Statefarm. For what its worth, USAA and Amica (AAA is also rated highest for claims) are rated highest in JD Power ratings for auto and homeowners.
Know someone that was in car accident caused by Allstate member. Person saw doctor once, wrote a letter stating that elbow pain for 6 months and wanted $6K. The next week, he got check for $5K with NO questions asked. Mercury, meanwhile, is ruthless and strongarms victims in attempting to bribe victims with $500 to sign indemnity forms day after an accident.