When comparing GroupMe vs Pulse SMS, the Slant community recommends Pulse SMS for most people. In the question“What are the best messaging apps for Android?” Pulse SMS is ranked 16th while GroupMe is ranked 23rd.
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 Multi-platform/Unified Messaging
Pro Open-source
Pro Per-Conversation Customization
Pro One-time fee
Pro Good Material Design UI
Pro Encrypted messaging content on devices
Pro You can use the iOS app as long as you know how to sideload it
It is on GitHub and there's a way to sideload it with Cydia impactor and appsigner.io
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 No RCS support
But only Messages has that.
Con Inconsistent and intermittently unreliable syncing with web app.
Forgets password periodically - dev insists that it doesn't do this - but it does.
Despite syncing via cloud there is no backup option.
Con The web and pc clients haven't been updated in almost a year. No support for gifs in the web or pc clients. Sometimes the web and pc clients are unable to login or do not sync messages.
Con Lacks support for UWP on Windows 10
UWP apps aren't hard to build - Luke K could bring his app to the Windows Store easily and make a TON of people happy at work.
