I use the Mattermost iOS app daily, and it works well on a good connection.

The iOS app is a feature rich experience similar to web and desktop apps, so when I travel and am on a slow connection it doesn't perform as well.

Here are our current mobile performance benchmarks so you can decide for yourself: https://docs.mattermost.com/deployment/push.html#mobile-perf...

There's work underway to get the mobile apps working better on slow connections.