When comparing Signal vs F-Droid, the Slant community recommends F-Droid for most people. In the question“What are the most useful Android phone apps?” F-Droid is ranked 7th while Signal is ranked 13th.
Ranked in these QuestionsQuestion Ranking
Pro Provides security and privacy
Signal uses an advanced end to end encryption protocol that provides privacy for every message every time.
Pro Free and open source
Signal is free and open source software, enabling anyone to verify its security by auditing the code. It's the only private messenger that uses open source, peer-reviewed cryptographic protocols to keep your messages safe.
Pro SMS/MMS support
Signal can be your default SMS/MMS text messenger. Encryption is not possible when sending SMS to your contacts, however.
Pro Recommended by Edward Snowden
Edward Snowden uses this messenger and recommends it to everyone who is concerned about his privacy.
Pro Supports encrypted group chats
Pro Supports sharing of various different media types
Signal supports: emoji, pictures, videos, audio, contacts, any location and GIF.
Pro Message mirroring on Signal Desktop
Signal Desktop is a Chrome extension that allows you to mirror messages from your phone, including replying.
Pro You can easily view all media exchanged
You can easily view all media shared in the chat without scrolling back to when it was shared.
Pro All titles are free and open source
All apps and games on F-Droid are free and open source (FOSS), making for a complete store resource for users who want to use only open source software on their device.
Pro F-Droid compiles all packages
F-Droid compiles all the packages themselves ensuring a high level of security. Other stores just allow the developer to upload the app already compiled, meaning anything malicious could be in the app.
Pro All apps have no ads nor tracking
This alone can be a great reason to use the apps available on F-Droid, but there is also the fact that this can increase battery life due to tracking and ads never requiring a data connection, since they are not present.
Pro File sizes are shown
For those running out of room, the size of the APK is always shown.
Pro Previous versions of apps remain available after updates
If you don't like an app after an update, you can download the previous version again. This is not possible on GooglePlay.
Pro Multiple repository sources
You have more than one source of apps and updates and local repository too
Con Single device
Signal can only be registered to one mobile device at a time. But you can link Signal to Signal Desktop.
Con Unreliable notifications
Sometimes messages won't be received if the Signal app has been closed for a long time or hasn't been opened after booting the device.
Con Needs access to your phone number and contacts to work
Con If SMS/MMS imported, other apps can't read SMS
For those using Join, Pushbullet, or similar apps to send and receive SMS/MMS from web or desktop, putting your SMS in Signal somehow breaks this functionally. The dev is aware but plans to remedy the situation have not been named a priority
Con Uses message mirroring
You phone must be on and connected to the internet for Signal Desktop to work.
Con No ratings/comments/number of downloads
All apps are presented equally. It is difficult to judge an app's quality/popularity before trying it. On the upside, descriptions are fair (written by the F-Droid maintainers, not by the app authors).
Con Small selection
F-Droid has a small selection of apps when compared to other major Android markets. This is due to every app being open source and given away for free, something not many people are willing to do with their time and creations.
Con Not all apps have screenshots
It can be difficult to tell what an app is like without installing it.
Con It doesn't have all the open source apps
There are many open source apps that aren't available on F-Droid due to their authors not making it available on that particular app store. One example is Omni Noted, which is on the Play Store but not F-Droid.
Con Updates are not automatic for non root users
You have to click the updates one-by-one in order to make them happen. If user has rooted their device automatic updates are possible, the app needs to be converted to a system app.
Con Descriptions are only available in English
Though the store app is multilingual, the app descriptions are only in English, meaning you must know English to find an app, even if the app is supposed to be multilingual.
Con A lot of apps lack polish
Since every app on F-Droid is FOSS and released for free, many of them aren't as polished compared to other markets and their paid app selections.