I have Progressive and I've never made a claim, but my rates were going up annually until I figured out why.  If you insure a new motorhome with Progressive they will guarantee that if you have a total loss in the first five years they will replace your motorhome with an equivalent current model year motorhome.  After five years, they will pay up to the purchase price of your current motorhome in the event of a total loss.  Sounds like a great deal, but that coverage cost money. 
I just discovered this when going through my insurance documents.  My 10 year old motorhome was insured for the amount I paid for it 10 years ago if it were to be totaled.  This is a great deal if your motorhome gets totaled, but not so great if it doesn't.  I contacted Progressive and they worked with me on it as the next issue was I owed more on the motorhome than it's worth.  So at first they told me I had to either keep what I had, or change it to actual cash value.  I didn't want to do that because that meant if it was totaled I'd still owe the bank money.  But the guy at Progressive I spoke with said he would check with underwriting and get back to me.  They got back to me within a week and agreed to lower my coverage to the current loan balance.  That cut the premium almost in half.  I'm paying this year exactly what I paid for insurance 10 years ago on it.  If it gets totaled they'll pay off the loan and I can walk away from it.