Hatchbox is getting in on the refillable spools game as well and it looks like they are falling in line with Microcenter / Overture with the same kind of masterspool
Available on Amazon, they look like they are a better deal than Microcenter (7.99 for master spool). For Hatchbox, they offer refills for $19.99 and Refill w/Reload spool for $25. So you come out ahead with Hatchbox.
Is Bamboo the driver behind this convergence on a single masterspool format? They also sell refills and masterspools. Seems like their rocket to the top would be an impetus for everyone else to jump in the refill game.
All of these masterspools have a peg that fits into a notch in the refill cardboard core, so I'm assuming these are all from the same mold, so to speak.