Downsides: There are pit toilets, and they smell pretty bad, and the sites are really close together. There is no trash, no water & no reservations. The good: Plenty of beautiful trees and shade. The creek is lovely, and a wonderful place for the kids to play. There are some fish, but hard to catch. The best thing is that it is free to camp here, and it's only 20 minutes from June Lake, and 20 minutes to Mammoth if you need supplies.
When I go camping, I like getting away from people, and Heart Bar is one of the campgrounds with bigger sites so we can do that easier. The sites are beautiful and clean, and there is a beautiful meadow to hike through, and you can drive 10 minutes to Jenks Lake for some fishing and lake views.
We just went up for the day (you can actually use the sites for $12 for day-use), and it was super quiet and lovely. Great views from all over the campground. It did start to get windy in the afternoon, and I think that might be true for most days because the campground is up on the very top of that part of the mountain. Most of these sites would be hard to get an RV in, and some of the sites are pretty sloped for big tents, but seems like a great place to get away! There are a couple of trails right from the campground too. Also there is a lodge open right next to the campground if you wanted to eat out for a lunch or dinner!