JOSM is an extensible editor for OpenStreetMap (OSM), written in Java.
JOSM vs StreetComplete opinions
They're really different use cases. JOSM is for detailed editing at a desktop or laptop. StreetComplete is for quick updates on your phone.
Vespucci is the first OpenStreetMap editor for Android, Codename "Vespucci", continuously improved and developed since 2009. It supports the full OpenStreetMap data model including lots of less known quirks and can be used, if necessary, completely offline.
Vespucci vs StreetComplete opinions
Streetcomplete is for checking and quickly fixing limited object data , but Vespucci is more detailed but not as quick and easy to use as Streetcomplete
Both are android apps, granting the ability to edit osm from the phone.
A dedicated app for collecting hundreds of POI for OpenStreetMap.
Every Door vs StreetComplete opinions
It's one of the few mobile apps that let you edit OSM but its on iOS unlike StreetComplete. You should still use StreetComplete in addition to this cause it's really good.
MapComplete is an OpenStreetMap viewer and editor. It shows map features on a certain topic, and allows to see, edit and add new features to the map. It can be seen as a webversion crossover of StreetComplete and MapContrib.
Map your environment simply and fast, directly from the app. Keep your eyes wide open and contribute to OSM while on the run.
Osm Go! vs StreetComplete opinions
I combine StreetComplete and Osm Go! on my walks: StreetComplete for solving quests, and Osm Go! for when I need to add some point to the map – often shops, bicycle parking or trees.