Harvest Host

Yes, we've used HH sites a few times. We only joined a few months ago, so haven't had time yet to use them a lot. Our experiences so far have been very enjoyable--we've done a winery, a farm and a wildlife rescue. We didn't travel more than a few miles off of our planned route for any of them. It's true that you're expected to patronize the business, but the amount we've heard suggested is $20.

The 1-2 nite max was a no no for us. We rarely stay less than 2-3.

Not by personal experience but I have looked at them:
1) $80/yr
2) One night boondocking MAY be allowed. If you get permission. They may give permission for a second night.
3) Sites are often well off of major routes
4) You are expected to spend $30 and up at the site

Does not seem to be a good deal to me. Unless you rally like touring winerys and not all the sites are winerys.