I too like using Reserve America. Makes it very easy and convenient to both reserve, and keep track of the reservations, which is nice for those who have to book the entire summer's worth of reservations well in advance to have a chance at getting a spot.
And, this summer, I had to cancel a weekend trip last minute (6 days out). Because I was outside of the 7 day cancellation window, in addition to the $10, I lost the first night's fee ($17) that we had already paid. It sucked, but it is what it is, and it was very clearly spelled out when we made the reservation what the cancellation policy was.