We recently camped here Labor Day Weekend, although we have stayed here a number of times over the last several years, and Zion Campground has become our default campground when the National Park has been filled up. I'll quickly summarize the pros and cons, and try to add my 2 cents to the many comments that have already been left.

Pros:
-Location: Very close to park, shuttle stop <5 minute walk from back of campground. Good restaurants within walking distance.
-Scenery: Nice views of the canyon from the entire campground, I especially like the riverside spots (drowns out night time noise as well).
-Amenities: I enjoyed the free wifi, pool, as well as numerous vending machines, movies for rent, and onsite laundry.

Jury's Out: Cleanliness: Some other reviews have been pretty scathing, but you have to realize that dirty bathrooms are pretty standard for campgrounds (not to excuse filthiness, but this has been my experience over the years). This last weekend, the bathrooms and showers seemed pretty clean and there are now soap dispensers in the bathrooms :).

Cons:
-Crowded: Campsites are small, neighbors will be quite close and possibly noisy.
-Lack of shade: I have only found this to be a major issue during the hot summer months.
-Price: $30/night seems a bit steep when National Park prices are half of that. Although, there are quite a few amenities on-site, so that may be a factor to consider. I don't like being charged $7/night more for 4 people (there's an additional charge per person above 2 people) that take up the same amount of space in the campground as 2 people :(.

I would recommend this place, but you have to take the good with the bad!

This was our last stop on a 16 night trip and I thought we would like the showers, but they were so filthy that my husband would not use them. I wore my shower shoes and was careful not to touch anything! As another camper pointed out to me, it is better to bathe in the river. The bathrooms did not have toilet paper and were also disgusting. We should have stayed at the park and will next time. If the park is booked there is another, better maintained campground down the road a bit. This was the dirtiest and poorest managed campground I have ever seen. Next time I will read the trip advisor reviews before making reservations. I hope this saves someone from the mistake of staying.

We stayed here for two nights. The place is very close to the Zion Canyon entrance, a short walk to the shuttle bus stop is easy to do. At the otherside of the road there is some kind of : adventure company": where you can rent stuff and go on hike with. We had a tent site located at the virgin river. Nice location for the tent. That was the good part.
The showers and restrooms were dirty and not well maintained. You can get tokens for the shower at the reception desk. One per person per day. You get 6 mins of shower for that. There was free wifi throughout the campsite, but there was no reception at the sites near the river.

This campground is okay. We stayed here one night because we were unable to get a site in Zion National Park, and that is the only occasion I would recommend staying here. The pluses: the campground is literally right next to Zion National Park and the Springdale shuttle stops almost directly in front of the facility, the restrooms have running water and showers, and there is a swimming pool and small playground which is nice for families with children. The minuses: at about $35 a night for a tent site, it's a bit pricey, the restrooms have no soap dispenser, the tent sites are small, offer virtually no shade, and are completely covered in rocks. It's like pitching your tent on a gravel road. Seriously. You get a token for the shower, and the water runs for only 6 minutes. That's a pretty speedy shower, especially if you're filthy from several days of backpacking like I was. All in all, for the relatively high price, I would have liked to have seen a few more amenities, at a minimum they could at least have soap dispensers. Like I previously stated, this place makes for a decent Plan B if you can't camp at Zion.