Messenger and Messenger lite Application uses for chatting through facebook. Although both Apps serves the same purpose, there are some differences which will help you in deciding on which one to download.
Messenger have chat heads which makes it easier to receive and reply messages while Messenger Lite does not have such a feature.
Messenger occupies more space in your device while Messenger Lite takes little space. This feature is a plus for people that have little memory spaced phones.
There is no doubt that Messenger consumes more data compared to Messenger Lite.
Messenger is faster during communication while Messenger Lite is a little bit slow.