When comparing Disa vs Facebook Messenger Lite, the Slant community recommends Disa for most people. In the question“What are the best Facebook messenger alternatives for Android?” Disa is ranked 5th while Facebook Messenger Lite is ranked 8th.
Specs
Ranked in these QuestionsQuestion Ranking
Pros

Pro Does what it's supposed to do, without bloatware

Pro Open source plugin API
Everyone can develop their own plug-ins.

Pro Easy to use
Disa is very easy to use and has an open source API, so many new services will be added soon.

Pro Customizable notifications
Ability to set different notification sound/vibration/led based on the plugin.

Pro Unified conversations
Ability to merge conversations from the same contact on different services.

Pro Friendly developers and generally good G+ community
Fast, decent replies to questions, even if they've been asked before.

Pro Many requested features
The developer team does actually listen to the community and adds requested features.


Pro Pushbullet support
Disa works great with Pushbullet, allowing you to answer from your PC.

Pro Many languages
Help and support in many languages.

Pro Disa takes privacy much more serious
Currently, the Disa team knows less about you than the website you're currently visiting.

Pro Great material design
With color-changing design with custom colors for each service.
Pro Gets features while staying small
It has received several features the full app has (stickers, voice and video calls) while the app size stays about the same.
Pro Can run on slow phones
Being light (installed it takes up 6-10 MB of memory) and fast, Messenger Lite can run on phones with Android 2.3 and up.
Pro Works on all networks
This app was made with 2G networks and areas with slow or unstable internet connections in mind. If you lose the connection, your messages will be delivered when you have signal again.
Cons
Con Doesn't support most messaging apps

Con Disa doesn't follow the Google Design Guidelines
Hamburger Menu/Navigation Drawer (Side Menu):
https://www.google.com/design/spec/patterns/navigation-drawer.html#navigation-drawer-contentNo Animations:
Empty Pages/States:
Maybe a Launch screen?:
Con Does not support Google SMS
Con Closed source
Disa is closed source, so the development speed is capped of their team, no external developer can help or add features that are not on the route of the team.
Con Doesn't support WhatsApp at the moment
Con Attaching pictures suddenly failed; no working solution.
Con Smaller development team leading somewhat slow implementation of requested features
Though the main development (framework, etc) is moving along fine, things like quick reply and sending multiple images at once should've been in quicker.
Con Constantly asks to re-authenticate WhatsApp
Con Doesn't let you customize notifications per conversation or contact
Con No secret chats
Doesn't support end-to-end encrypted "secret chats" like the full app.
Con Doesn't support deactivated accounts
The full app has a feature where the user can deactivate their Facebook profile, but continue using Messenger. Lite lacks that feature.
