The sites are very spread out, and not very consistent in size/quality. We were able to nab site 112 and it was fantastic: lots of space, and privacy too. It was next to a road, but one with very little traffic. However, we drove past some sites that looked sad and offering no seclusion.
Personally I think the seclusion is well worth the price, but it's worth mentioning that to get potable water we had to drive ~20 minutes. Same deal as far as the for-better-or-worse, but we had no cell service at all for most of the area.
Finally, the Cornucopia Café just outside the park is A MUST VISIT. Inventive menu, friendly staff, outdoor seating, we were pleasantly surprised and will return.