To begin, the lots are far enough away from fellow campers that you're seldom disturbed by noise or movement. During the day, there will be plenty of new faces passing through to get to the Black Canyon Loop, which has its access point at the back of the camping property. There are, I believe, three pit toilets (possibly four, but I only recall seeing 3, one at the entrance, one on the right hand side up the pavement, and one before the trail access point).
The trail is phenomenal. The incline is quite steep, but the loop is a reasonable length and I've seen families with young children and elderly folks successfully complete the loop. In the spring and early summer a small (VERY small) stream cuts through the trail from the snowmelt.
You're likely to encounter wildlife in the evening if there aren't many campers, as bears are everywhere here. While HIKING at this location in the off season (site is closed for winter, but you can still access the trail) my wife and I encountered large mountain lion tracks.
Parking at the lots is limited, with most spaces only fitting one car comfortably, and the space for tents varies but isn't enormous.
Overall, a very cozy, shaded, quiet campground right off the main road making driving up or down the mountain for more trails during your stay very feasible. I personally have no cell service here, and use Mint Mobile, as a heads up. There is a functioning payphone near the entrance.