Any where near the water is a great place to camp! This place is awesome for boating, kayaking and canoeing, and the fishing is always great! I love going here
I've stayed at this place twice, once as a base camp for a Rainier trip, and another as a weekend getaway. It's about an hours drive from Paradise, which makes it less ideal than Cougar Rock if that's your destination, but the reservations do not fill up nearly as quickly.
The facilities here are great, water taps throughout the grounds, and clean bathrooms with showers nearby. Many campsites are not adjacent to the parking but there are wagons to use to ferry your gear. Make sure you check the reservation website because there are extensive descriptions of every campsite and drone photos. In particular, on my last trip I didn't think much of where it said that the tent pad had an extreme slope, which turned out to be pretty uncomfortable to sleep through…
There are tons of families here, depending on whether you have kids, the family-friendliness may be a feature or a bug. The campsite is pretty loud until around 10 when the kids go to sleep. The campsites are also pretty close together which doesn't help, but this is again something you can look for when choosing a site. We chose a site further from the parking lot, and the nearby sites had less kids than the ones right on it.