I've used two online firms (Progressive and Geico) and one mom-and-pop while living in Cambridge. I have no clue why there isn't a bigger national-firm presence! I can tell you that when my car got hit by a truck--a no-fault accident with serious damage--Progressive communicated directly with an in-network auto shop to assess repairs. The experience of getting in a serious accident was horrible, but my insurance experience was ok. It didn't matter to me that there was no field office. I got my car fixed & my record cleared, which is what I wanted.

I left the mom-and-pop shop, which was also fine, because this past year my insurance doubled in price for no reason. After confirming that I wasn't misinterpreting anything, I bailed for Geico. Based on the convo with the insurance agent, I think it's a tough year for the mom and pop shops, and they're getting more expensive across the board. But YMMV.