I use the Horizon 868 8V1 antenna together with my LPS8-gateways. This is an selective antenna for 868 MHz, its gain is compensated by the loss of the coaxial cable between the outdoor antenna and the indoor gateway.
The most limiting thing for the coverage is the Line of Sight. Theoretically the coverage is more than 300km with SF7/125kHz and more than 1200km with SF12/125kHz (14dBm ERP, Semtech SX1276). But if there is something in between disturbing the Fresnel-zone the coverage will decrease significantly.