I've yet to find something that unit does better than a Sony camcorder, telescope adapter, and a £35 odicforce.com ir laser. Battery attaches to cam. Cheap Li-ion rip off batteries.
£150 max vs £399 for the ns50 which is half the range.
My comment is completely unqualified, not having used the nite site units, but from experience of the DIY arrangement, nite site would have a hard sell convincing me to change.