I currently have Erie for everything.
I agree with others that it is worth shopping around every few years.
I am also not loyal to one company. But have 4 different policy's that I prefer to ALL be with the same company. Thats personal auto on 3 vehicles, Commercial auto for my truck, business liability to cover my ventures with the tractor as well as snowplowing for whatever part the commercial truck ins dont cover. And my house.
When I only had auto and home.....I had home with state farm....just because thats what the mortgage broker recommended when writing the loan, and it was escrowed and I never messed with it. And I had progressive for autos, as they were the only one that would cover a young unmarried male, with something like 10 speeding tickets in a 35 month period.
After all those lapsed and and I got married....I shopped. Settled in on state farm to match the homeowners ins. Kept shopping every few years and no one was any better when comparing apples to apples. All were right in the same ballpark and at best....maybe $10/yr cheaper on the package deal.....which wasnt worth the hassle of switching and dealing with the escrow setup.
I switched to erie several years ago on account of needing business ins. State farm had some policy that they would no longer insure any business that hasnt been previously insured for at least 2 years. So I called about 3 different independent agents to shop. Erie, pecan, ohio mutual, grange, allstate, nationwide, state farm, auto-owners, geico, etc etc. All of them would be priced just by dealing with a few independents.
There were slight differences that I had to adjust to be able to compare apples to apples. IE: most "standard" policys cover dwelling extensions (detached buildings) at 10% of the homes value. Well, with having a nice shop at my old house, and now at my current place....10% wasnt enough. erie does 20% as their standard, as do some others, but the ones that only do 10%.....gotta have them bump it to 20% and re-compare. Deductibles is another one to make sure you are comparing apples to apples on.
In the end, I have commercial on my truck/trailer, and 3 personal autos all insured to the max which is something like 250k/500k w/300k liability....I have my home insured with the shop covered at 20% of the home value (which is sufficient), and I have a 2m/4m business liability policy. All of that cost me ~$250/month.
With 4 policies comparing the total as a whole, erie was the cheapest apples to apples. IF I wanted 4 different carriers, like allstate for autos, erie for business, auto-owners for home, and ohio mutual for comm truck.....taking the cheapest of each itemized quote....I could have saved ~$10-$15 per month. But for me it wasnt worth the hassle. $240/month broken up over 4 separate bills. Or $250 and one bill and done. And if I have any issues.....its one call. Dont have to worry about weather a claim should go on my commercial truck ins, or business ins if I damage something plowing, etc. And about every year or two, I call around again. no one has offered me any better yet.