I guess every insurance company has happy customers and unhappy customers. When I started in law enforcement 46 years ago, officers had to carry their own liability insurance for driving police vehicles (emergency vehicles). In those days government agencies (city in my case) were immune to lawsuits for motor vehicle accidents. In other words, should a city employee have an accident that was his fault, the other driver or injured party could sue the employee, but not the city. The older officers warned new officers to avoid Allstate Insurance. We could buy a separate policy for that liability, but it was cheaper if your own auto insurance company would just include a rider to cover that liability. Officers said if you ever had a claim of any kind, Allstate would cancel your policy, and in Texas at least, if one company cancels you for any reason (or no reason), all the other companies charge higher premiums.
Of course, this was a long time ago. One of my brothers has had Allstate auto insurance for many years, has had one claim when his wife wrecked their truck, and is happy with Allstate.
When we moved back to town in the Fall of 2002, and rented an apartment for awhile, I did a little shopping and bought auto and tenant's insurance cheaper with Allstate. Then in the Fall of 2003, I bought a mobile home and Allstate refused to insure it because I'd had a water damage claim on a prior mobile home in the past 3 years. In May, 2002, I had a mobile home insured with a good insurance company and the water heater sprung a leak. The adjuster came out on May 20, 2002, inspected the damage, and wrote me a check for $1,160 on the spot. And that was the reason Allstate refused to insure a mobile home for me.