I already have a Search4Sites subscriptions — is Park4Night better/worse/the same?...
I have both and Campercontact,
P4N, has to most number of park-ups it's more basic on details and lacking many pictures, but for hardcore off grid campers it's very useful. There a lot of issues with some site being abused with push back from locals and police, with some blocked off, but its mostly in high season and mostly directed at the big whites especially from certain countries which seen to think they have a god give right to do what the hell they want, July August we are normally hiding somewhere or home so haven't had any issues, in fact unless you are following the snow birds down to the South of Spain most places are empty off season.
Campercontact, is a bit more polished but not as many sites as P4N.
Searchf4sites, has the least number of sites, but has a very good map, site detail is very good.
I think it depends what you want and where you go, we wonder all over europe but prefer the Alps/mountains from the French coast to eastern Austria, in comparison one location we often pass, Mont Cenis Lac + 2,000m in France just over the border from Italy, its 2 1/2 hrs from home.
P4N - 3 parkups, 5 wild camps,
Campercontact - 3 parkups
Searchf4sites - 1 parkup
These are all very busy in season, but off season after the snowmelt in spring and before the winter snow it's relatively quite in the evening unless a bunch of big whites turn up.
All have apps for iPad and downloads for Garmin etc