When comparing Signal vs QKSMS, the Slant community recommends Signal for most people. In the question“What are the best messaging apps for Android?” Signal is ranked 2nd while QKSMS is ranked 11th. The most important reason people chose Signal is:
Signal uses an advanced end to end encryption protocol that provides privacy for every message every time.
Specs
Question Ranking
Pros
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 sharing of various different media types
Signal supports: emoji, pictures, videos, audio, contacts, any location and GIF.
Pro Supports encrypted group chats
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 Allows responding to SMS without opening the app
When a new sms is received, a window will pop up that has the message and allows answering it from there, without having to open the app. It can be dismissed by tapping anywhere else on the screen.
Pro Free
The app is available for free with an optional donation IAP that ranges from $1-$10.
Pro Per-conversation notification settings
Users can set different notification settings per user as an easy way to know who is messaging without having to look at the actual message.
Pro Readable in day or night due to themes
There are light and dark themes available within the settings which can be switched depending on how light it is around one when using the app. The dark theme can also help to conserve battery when being used as not as much brightness and hence battery will be used.
Pro Beautiful design
Responsive, highly customizable Material Design interface makes for a native looking app that fits in well with Google's UI design guidelines.
Pro Save yourself from sending out bad messages
Through delayed messaging one can set it up so that a message is not sent automatically. This can help for those times that it may be best to think something over before sending out a rash message.
Pro Very active developer who listens to the community
While QKSMS is one of the younger apps, the developer is quickly adding features/fixing bugs.
Pro Convenient Android Wear support
Those that own an Android Wear device will be able to set it to receive their messages on the Android Wear device making for convenient notifications and easy messaging through not having to take their phone out.
Pro Easily communicate with groups
Users can communicate with large groups at the same time due to the included group messaging feature. This is convenient when trying to synchronize with friends or colleagues.
Cons
Con Single device
Signal can only be registered to one mobile device at a time. But you can link Signal to Signal Desktop.
Con Needs access to your phone number and contacts to work
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 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
Con Buggy
There are little annoyances here and there, from dark theme problems making text unreadable to crashing and missing notifications.