There is no long haul with 3DR. There done building Quads. The technology certainly isn't dead. Parts are a bit of a problem. The following is how I see it. I have a DJI F450. Its equipped with a Pixhawk, Telemetry, FPV, camera gimbal, and I run Ardupilot on it with Mission Planner as a GCS. It cost me about $700 to build the F450. Given the fact that the Solo bundles come with extra batteries, its like two Solos = my F450 dollar wise. Is the F450 easier to get parts for? Yes. But the Solo is a great Quad that's ready to fly without having to understand how to tune the open source firmware.
Regards,
David R. Boulanger