When I was first driving back in the 1980s, my parents used Allstate, and since I was insured under their policy I had Allstate. When I was out on my own in my early 20s, I continued to use Allstate for many years. I never filed a claim with them so don't really know how they were to deal with.
The last two or three years I lived in Portland, I had insurance through a local insurance broker. They found me great deals through the very reputable lines of insurance they carried. I was paying 40-50% of what I did through Allstate. Wow.
When I moved to Texas in 2008, I got an insurance broker there too. For most of the 10 years I lived there, I had all of my cars insured through The Hartford, plus homeowner's and supplemental umbrella policy. Never filed a claim through them, again, but the rates were quite good. When my 560SEC got sideswiped by the semi in late 2016, it wasn't my fault, so the trucking company's insurance company paid, and my insurance really didn't get involved. The Hartford would only insure my G-wagen as liability only, because it had a salvage title (the classic thing where somehow the rear bumper was hit (no mechanical or body damage -- I have all of the photos) and the vehicle was totaled for literally a broken rear fiberglass bumper, and a broken rear mud flap. Totaled.
The great thing with an insurance broker, is that they carry multiple lines of insurance, and they will (every year) price out renewals with all of the insurance they carry and get you the best deal. In effect, they do the shopping for you, and your rates stay very low. Of course, they would come to me at renewal time every year with an option or two, sometimes with a slightly lower deal, or better coverage for the same price, etc.
When I moved to Maryland I went with another broker, whose primary line of insurance they carry is Erie Insurance. Erie is a regional insurer in the Mid-Atlantic and Northeast area. I have been very happy with them for the past three years. Rates are overall about the same as with The Hartford in Texas, and I've only had a couple of windshield replacememnts on Laura's Lexus (no car damage). They've been super easy to deal wiith and most stuff can be done online, good web site, etc. We use Erie for homeowner's, umbrella and car insurance. They provide full coverage for my G-wagen, no problem.
It was interesting -- Laura has a friend who is a State Farm agent, who she used to use for her insurance before we met. He was not able to insure us because of two reasons: 1) he could not insure both of our cars on one policy, because we were not legally married; and 2) he could not provide us with homeowner's insurance because I had made a homeowner's claim within the last three years (at that time -- I had made a homeowner's claim in Texas for my house roof due to hail damage).
I think the guy was a bit embarrassed by both of those reasons -- it wasn't like I could control the homeower's claim because I can't control whether a hail storm happens or not, but he had to go by their corporate rules.
Erie Insurance didn't/doesn't care
whether we are married or not. But I guess that won't be a factor for too much longer, anyway...