They are definitely expensive. I like the UI, it’s pretty handy. I can connect to the MPPT controller via Bluetooth, check the BV and production profiles, know when to go clean the panels…in the long run on a primary source system, I think the cost is worth it for the configuration flexibility alone. I’m also building a second water wheel powered AC input, having the dual input prority programmable options is going to be key to eliminating the grid altogether, or using it only for system failure.