Also known as AARP, The Hartford was the recipient of the 2016 J.D. Power study for car insurance companies ability to handle claims. The Hartford scored 5/5 stars for nearly every step of the claims process; from notifying them, to the repair process, and the final settlement. Those who think a smooth claims process is the most important factor for car insurance, The Hartford should definitely be considered.
While State Farm's shopping experience is well-reviewed, customers did not feel as strongly about it's claims handling process. The company scored about the same as the other four large companies, but was still mediocre. A large national company may be expected to not be very efficient because of the various departments involved in handling individual claims. If you want the assurances guaranteed to you by a large, "legacy" carrier, then State Farm is the best to go with.
All classic car insurers share a few vital elements. Primarily, they all have an "agreed value" stipulation which allows you to set how much you think your vehicle is worth in the event of a total loss. They also all provide pivotal comprehensive and collision insurance to protect your vehicle from anything that may damage it. There does exist however, several key differences. While the field of companies for classic cars is not as vast as it is for normal cars, some classic car insurers are better than others.