We loved our 4-night stay in Big Meadows. I definitely recommend booking a site on the outer part of the loop, or one of the walk-in sites, if you are tent camping. A lot of the interior sites seemed very close together, but the farther out you get, the more spaced out they seemed to be, we could see a couple of other campsites from ours but generally felt we had plenty of space and privacy.
Campsite facilities seemed pretty clean and well-maintained, and there is the campstore at the front of the campground with necessities, laundry and shower (for a fee). And if you need more the Big Meadow visitor center, and Wayside souvenir store/snack bar are just a mile or so from the campground where it meets Skyline Drive. They even have a gas station there. We went and did several hikes, including Dark Hollow Falls, and spent a late evening in the Big Meadow on a picnic blanket stargazing, all very close to the campground.
Bear boxes are big and sturdy, fire pits are on the smallish side but fine. Honestly this place is pretty tough to beat in terms of facilities, value, and proximity to a lot of beautiful and fun national park hikes and sights.