All of my offsite stays started when my daughter was in 2nd grade. She was on a school schedule of 9 weeks on / 3 weeks off. I had some vacation available in Dec outside of the XMas vacation. I didn't have someone to watch her for a week and a 1-week camp was about $300. I found WBC online for $500 in a 2BR unit. I decided it was worth a try and worse case we are in FL out of the cold and grey. Then, mom wanted to go and her friend wanted to go. So, we split it 3-ways. It was the absolute best trip we ever had. That is what sold me initially. Now, I did stay onsite a few more times after. We got DVC 1BR units for $1,000 and $1,200. Those were great too, but those are extremely rare. My experience in offsite rentals go like this:
WBC Dec 2014: 2BR $500
SSR July 2015: 1BR $1,000
WBC Dec 2015: 1BR $500
WBC June 2017: 1BR $560
OLR June 2017: 2BR $700
Reunion June 2017: 3BR $550
If you add all of those up, it is the same price Disney charges for a 1BR for a week over the Summer months. The SSR was through an RCI exchange, so not exactly legal, but they can be had. The down side is if Disney finds out about it, they can cancel the reservation.