[SamWhited]

I first started using XMPP heavily in 2014 when I was thru-hiking the Appalachian Trail. Much of the trail has extremely limited cell coverage (even if you can get Edge some of the towers are so bad you can literally only get a few bytes per second). I evaluated several different protocols and apps for communication with family, and XMPP beat them all hands down every time. The long lived TCP connections meant that once a connection was established I could keep it up and it would sit there slurping up the bits as it came. That experience later led me to get involved with the community and even write a spec about using XMPP on high-latency low-bandwidth networks.

It may have been bad at this at one time, I don't know, but at least since I've been using it's been fantastic with poor network quality, I suspect the people saying otherwise are just repeating something they learned in the early 2000s that's no longer true.