I have mine under progressive. I have my autos with them and they've been so easy to deal with so far, including when I had a claim from hail damage to the car. They sent a guy out to look at the car and I was able to use whatever body shop I wanted.
Mine has liability, of course, but is also insured against weather (I get tornadoes and storms with winds up to 80 mph every year), against the uninsured, and if I were to break something big.
Mine's an '04 H260 and I've got it covered for 25K and pay about 30 bucks a month. I'm pretty much a newbie sailor since document wise, it's my first boat. I could pay less if I increased my deductibles. The trailer is included.
No surveyors or anything. You get a choice on whether you want to insure it for an "agreed upon" price (basically you set the price as long as it isn't ridiculous) or fair market value. If you go with fair market value, someone has to come look at it. I went with the agreed upon price.
I had a quote from BoatUS. They were a little less expensive but just not as easy to deal with. I can make changes on my policy through progressive whenever I want. I can print out documents when I need to and all without making a phone call and waiting for snail mail. I had actually gotten the boat in possession and the next day forecasts were for some severe storms and tornadoes. I wanted it insured that day which BoatUS couldn't help me with.
I haven't made a boating claim with them yet, but like I said earlier, they were really easy to deal with in the auto department when I made a claim. I had a top notch body shop repair the car and wasn't out a single dime for it. They had their estimate, the body shop told them what it will cost and the two of them worked it out, no big deal.