The main reason for wanting to use Blackphone is typically privacy, to gain as much control as possible over the privacy.
Some reviews (mainly from 2014) related to Backphone 1:
The big difference to normal android is the lack of the Google in this phone. This means that one have to get the applications from somewhere else, either using other apk-storages or limiting yourself to open source applications only and use F-Droid to get applications. The phone has build-in detailed privacy settings for each application, something that has been lacking from normal android until android 6.
After some learning curve, getting used to
- F-Droid: way how to get other applications
- OsmAnd~ OpenStreetMap for Android, offline/online maps and navigation
- Firefox Web browser
- Email, email client, build-in in blackphone
- Auto-Away Auto respond calls and messages
- FBReader e-book reader
- Diktofon Take voice notes
- Applications Info Show metadata of installed applications
- spaRSS Feed reader
- Sky Map Sky Map to explore the skies
- Document Viewer Viewer for many document formats
- World Clock & Weather Display local time and weather conditions
- “MyPhoneExplorer Client” This is the android client for MyPhoneExplorer, this is not available from F-Droid. (Available in several apk storages, for example here).
Blackphone also comes with the concept of Spaces. It is possible to create isolated spaces, each of which have different applications running and can be protected with different PIN codes.
Blackphone has build-in panorama camera mode. One can get quite nice pictures, please see below.
When limiting to the application list above, then the experience has been positive. If I compare android 6 and blackphone from privacy perspective, I feel more confident with blackphone. Naturally it also depends on which applications you are using.