So, in my experience, #MeshCore > #Meshtastic and for the simple reason that MeshCore gave me the tools to diagnose and solve all the reachability problems at my house.
For one thing, meshcore makes a distinction between repeater nodes and other types of node. Rather than have every node on the network do repeating, it requires purpose-installed repeaters, with different firmware, be deployed.
You would think that would make reachability worse, but it decreases the number of hops to get to a destination, meaning you can easily get from San Diego to Santa Barbara (about 200 miles) without getting halfway up the maximum hop count.
And from my house I could easily see that there were no consistent local repeaters I could reach. So I installed one! And it had the same problem, so I repositioned it until it had multiple reliable paths out. My repeater now even provides a new redundant path from the urban areas to my South, up a major highway to the Northeast or to a mountaintop 50 miles due North.
I never had a consistent connection with Meshtastic, and perhaps I could have done the same thing, installing a solar repeater in my front yard, but without dedicated repeater infrastructure I had no way to know whether there was a sane route out. Public chats in Meshtastic for me are all one-sided with people replying to messages I never saw, and nobody seeing what I’m sending out.
In Meshcore there’s an active community and I actually get to be a part of it. I’m sold.