Iain:
FWIW, I've had the same kind of problem even with State Farm when it comes to policyholder vs. policyholder. I think most all of the companies try to force those into "no-faults" so they can get the most deductible.
My experience involved a 16 y.o. skidding entirely through an intersection and tagging the right rear of my CRX hard. She admitted guilt at the scene (it was painfully obvious), but then her father got into play and tried to blame me. State Farm declared it a no-fault despite ample evidence (location/type of damage on the cars, skid marks all through the intersection indicating speed MUCH greater than the limit, etc.).
I learned a pretty good lesson from it: Your insurance company isn't responsible for your liability in accidents -- you are. Your insurance company only contracts with you to cover it. Seems like splitting hairs, but makes a difference in cases like this. I just filed in small claims court against the girl/father. They flipped out and called State Farm (who's obligated to defend them). When State Farm called me (promptly). I explained that if they can't see from the ample evidence, I'd just take it to the judge. Realizing that even if they did manage to successfully defend in the stupid small claims court their $500 gained from my deductible would be long gone, they changed their mind and declared it the girl's fault. Go figure. :)
I can't help but think that even $500/year is the equivalent of ~$41/mo. A meal out, once a month. I'm not necessarily recommending that everyone jump to State Farm, but at least a widely-recognized company that can support a claim. (Like, for example, one of the companies large enough to have no-adjuster-required or onsite adjuster agreements with major repair facilites.)
As far as which company, heck, I think they all probably have ups and downs. I suspect that YMMV more because of the agent than the company (assuming it's one of the majors). As far as me personally, I've had the same agent since I was 15 in Burkburnett, TX, and they've carried me through some tough times so I'm pretty stuck on them. To put it in perspective, if their office was to say, "Oh, we're XXX company now," I'd be right on board...
Chuck
PS: For those of you wondering why a guy with two Miatas is spending time writing War-n-Peace posts about bull instead of Miata-related stuff, rest assured I'm wondering, too. Damn. I think it has something to do with not being able to get outta the house recently, much less able to drive the Miatas. I'm truly bummed I missed the Frisco-start drive. I'll be on-board for the next one for sure.