WMF currently use Netbox for IP address management (IPAM) and datacentre inventory management (DCIM). It drives many aspects of our infrastructure automation, not least our network configuration.
Our currently deployed version of Netbox in production is v2.10.4, which can be migrated to Nautobot with relative ease. There are multiple changes to the back-end in Nautobot however, so if we upgrade to a more recent version of Netbox any potential migration to Nautobot afterwards would be a lot trickier.
I have created this Google doc to facilitate discussion and documenting the pros/cons of each solution. We can use this task to track the ultimate decision.