I've never considered Joshua Tree one of the "crown-jewel" national parks, and yet people are now flocking here as if it is. Black Rock is the first campground I have ever stayed in at Joshua Tree, and here are my thoughts. 

I'll start with the good:

If you're looking for Joshua Trees, this is a good place to camp because they are plenty throughout the campground. Many of the other campgrounds in the park actually don't have the trees; This campground has running water and clean bathrooms with flush toilets. This is actually a luxury when camping in Joshua Tree because most of the campgrounds have no water and just vault toilets; This campground has a lot of hiking opportunities without having to drive. There are actually tons of trails that lead directly out of the main camping area, so if you're not in the mood to even leave the campground, you can still experience a lot of nature; There is actually a small visitor/nature center located in the campground. Again without even leaving the campground you can get a lot of information about the park; This campground takes reservations(for peak season), which is also a luxury here because only a few campgrounds take them. And be sure to reserve because this campground fills up fast!! For these reasons, I think that Black Rock makes for a really good overnight/short stay, as you can see a lot in a such a small area. 

Now onto the not so good: 

A lot of the campsites are pretty close together. There were some spots that seem more ideal and secluded, but be prepared for close proximity to neighbors in most sites; Neighbors/clientele can be very noisy, and I mean noisy in a number of different ways. There was loud music that was audible far beyond campsites, but that was not the most annoying part. Over all it seemed like this campground was actually pretty quiet, that is until it was actually quiet hours! . An entire boy scout troop decided to roll in and set up an entire base camp right next to us after 10pm. Needless to say, it was very loud and bright until at least midnight. Good thing we had ear plugs; The campground is very close to the town of Yucca Valley, which some might consider a good thing, but there are neighborhoods literally built right up against the campground, so it doesn't really feel secluded at all here. When you hike up the trails and look back you can see the cityscape/city lights in the not so far distance; The wind can get really crazy. I don't know if it was just a freak weather event, but the wind was crazy both days I camped here, and it got so bad that we tore down our camp in the dark and went home early because there was no way we could have slept with that much noise and freezing wind blowing; It's kind of hard to find your way through the campground because there's no signage indicating which loop is which; The firepits were extremely full of ash and needed to be cleaned out; Lastly while the campground is technically inside the national park, it is not connected to the rest of the main part of the park, so you have to drive out of the campground about 20 minutes through the town to access the main park; Also firewood is not sold on site, so you must bring your own from outside. 

Overall, the campground is fairly decent with nice bathrooms and plenty of trail access. If you are looking for a quick and easy trip to experience nature and a national park, this is a good place to go. But if it's desert solitude you're looking for, you may be disappointed by the dgaf clientele and the proximity to civilization.