Until N-central 12sp1, we could search by the "Customer" and "Site" columns. Bug "fix" NCCF-7996 (I'm told by support this was done on purpose) broke this and we can no longer search by those fields. It was much, much faster to filter down to all devices from a single Customer or Site by search instead of drilling into Customers and Sites.
We even named all our Customers with this in mind. EG: "aatc - 437 - An Awesome Test Company", so that we can search by "aatc -" or "aatc - 437" and always get only devices of that Customer.