When comparing GroupMe vs Slingshot, the Slant community recommends GroupMe for most people. In the question“What are the best messaging apps for Android?” GroupMe is ranked 23rd while Slingshot is ranked 43rd. The most important reason people chose GroupMe is:
GroupMe has a built in function to read receipts.
Specs
Ranked in these QuestionsQuestion Ranking
Pros

Pro Reads receipts
GroupMe has a built in function to read receipts.

Pro Great web client
GroupMe has an excellent web client that can be used to send and receive messages and manage groups from the desktop.

Pro IFTTT Integration
Allows sending messages from web services via IFTTT.

Pro Integrated calendar
It's possible to add location and time with reminders directly in the GroupMe app.

Pro Makes it easy to silence 1 or all groups
GroupMe has settings that allow muting a single group or turn off all GroupMe notifications from within the app.

Pro Does not require everyone in the group to have a smartphone
GroupMe can set up a custom phone number which allows people without the App to send and receive messages. This makes it easy to add anyone to messaging.
Pro Send to receive nudges users to interact
Requiring users to first share a photo or video before they can view photos and videos from others makes it more likely that the other person will respond.
Pro One tap photo and video sharing
The first thing that the app presents the user with is the camera enabled and ready to take photos and videos. Photos and videos can have text written on them in white letters or drawn on with various colors and brush sizes.
Cons
Con Drains battery fast
GroupMe, in order to have a constant connection which allows for notifications drains the battery of a device quickly, which is not ideal for a messaging app that one needs on time notifications from.
Con Send to receive is unintuitive
Requiring users to first share a photo or video before they can view photos and videos from others can often feel frustrating.
