I'll chime in and note that we, too, are Allstays users and have been for a couple of years now. In Idaho, there are a larger percentage of campgrounds that are missing from the app, though it definitely has all of the main ones and many very tiny campgrounds with only one or two sites. I'm not certain why it is less complete in Idaho than in other areas where we have been, perhaps because some of the locations were likely out of range of any cell tower, making it necessary for any overlooked campgrounds to be added once cell coverage could be found. But it is pretty awesome, and it paid for itself the first time we used it.
We really like it because it enables us to plan bicycle routes through remote and rural areas that don't force us to do long days in the saddle just to bridge a long gap between campgrounds, and it allows us to avoid the big tourist destinations that Adventure Cycling maps force you to ride through. Being able to ride on lightly traveled roads and see places that most people would have no reason to visit is a big plus for us. But then so is spending a week or so at a time without cell coverage, allowing us to recall what it is like to venture into the world without knowing what the weather will be, where the big hills are located or where the next grocery store will appear - to just take things as they come (but still have some idea how far we need to ride and where we are likely to find a place to camp).
One feature that I don't think anyone has commented about is that the app will give the distance between you and a particular campground that you are interested in (provided you set your phone to give it your location). These are strictly as-the-crow-flies distances, so they are nearly all understated by the degree to which the route to the campground varies from a straight line (more of an issue for someone traveling under their own power than someone whose only exertion is the pressure applied to a gas pedal). And distances given in the directions to the campground are very hit or miss. Some are spot on, others are off by a fairly significant margin (and a few are just plain wrong).
