I furnished one for our local POCO to install on our customer's house. The utility had only put five in Ohio, and it took some phone calls, but they agreed to allow it, and charged a hundred bucks or so.
From my research on this protection, this was really a great way to go.
Location is outside, the grounded conductor can be kept very short, high surge withstand, and it has a large single 53mm MOV, which is better than multiple elements, as far as I can tell.
I had dual rods connected to the meter base, which I believe is preferable to panel-only GECs for surges with a ground relationship.