I went with Progressive, the same is my auto policy. Of course it depends on your boat, where you live etc.
Since I trailer, I liked having the same company as my SUV. Just in case... no pointing of fingers.
I did try US Boats but they were quite a bit higher. An added bonus, I got an additional discount because of the boat on my auto insurance.
Mine is a 26', no one asked for survey or pictures. that I remember, it's been about 5 years.
Side note, my boat sits on the driveway the majority of time. I called Progressive about that and asked about cutting back on coverage in the off season. Surprisingly, they said sure, no problem. So we dropped the excess liability coverage as well as a few other things. It really dropped the cost. He said just call them when I'm headed back out with it and they would put the old coverages back into affect. When I asked them how often I could do this during the term of the policy (I thought maybe once?) he said, when ever I use the boat. When I get back from a few days on the water I could go back can cancel the higher limits. "I said are you sure???" He said no problem, they do it all the time.
That wouldn't work on a boat that stays in the water but for a trailer sailer it makes a difference. I'm not really planning on switching back and forth every weekend but it's nice to be paying less in the off season and gives me more options.