They are implemented a bit differently. The chatty nature of Meshtastic works very well in small groups, or unknown area, when you need to talk a bunch of your friends scattered during a trip, to monitor your tracktors on a large field, etc..
Then you try to scale it to a larger city and it just completely breaks. Then Meshcore.io enters the picture. Every larger community that switches says the same - it's a huge reliability difference. It also comes at a cost of some discipline and more infrastructure planning (repeater nodes).
The more I play with both the more I respect both projects.
As for Reticulum, I don't see it competing in the same category at all. It has much higher aspirations, but also it seems at the moment it's much less practical and popular.
Indeed, but when talking to friends who find Meshtastic / Meshcore interesting we often also talk about Reticulum as it has some overlaps and is an interesting project.
If you are going to have the setup and work of repeater nodes though doesnt something that gives actual network use between devices make more sense?