The OpenStreetMap ecosystem (e.g. Organic Maps as an Android Client) is better than Google Maps.

Tusky is better than any proprietary Twitter client.

F-Droid and Flathub are both better than Google Play.

Thunderbird is better than GMail

Real open Podcasting (e.g. Antennapod) is better than Spotify.

OpenDesk is better than M365.

Signal and Matrix are both better than the chat tools from Meta, Apple, Google.

(It's about ecosystems/platforms, because most software doesn't work in isolation)

Lets not forget about games!

Hedgewars is better than most "Worms" games.

Warzone 2100 is more fun than many proprietary RTS games.

and OpenOffice and VirtualBox

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