We are heavily invested with GHL gear.
We've got three Profilux 4 controllers, three Mitras, three Doser Maxis, three Doser 2.1's, three KH Directors combos, one Ion Director combo (soon to be 2), two Expansion Boxes, and five PowerBars. We also have a bunch of sensors and controllable valves for individual tank top-offs and automatic water changes.
We basically run an automated fish store out of our house, with each Profilux controller responsible for a front end coral & fish retail system, a back end coral & fish quarantine system (not connected and in two different rooms), and our display tank that started it all. We save a ton of money in the long run by not having to pay for labor.