My real world experience is both Progressive and AmFam have taken my money for premiums every year for stated value coverage for, now, 3 different RVs.
I’ve had no issue with them. They are very good at accepting my premium in exchange for a policy that covers what I’ve asked to be covered at the limits I asked for.
Or in other words, shop around and find what you want.
I’d recommend either one although we dumped Progressive because they got real progressive with our rates a few years ago.
If you’re wanting to know about only people who have collected on a full totaled RV payout, that list will (hopefully) be pretty small.