5.8GHz is (slightly) more easily blocked by obstacles in LOS but on the other hand, for a given size, a 5.8GHz antenna can have much higher gain which helps to mitigate that. In fact, if you're using 2.4GHz you won't have guaranteed control when you're not LOS anyway.
My concern about 1.3GHz is that it's not legal in most places. Okay, if you're using 1.3GHz you're not likely to have black helicopters tracking you down and confiscating your model but the reason it's not legal is probably because there is something else using that frequency. What if that "something else" suddenly obliterates your FPV video signal when your model is out of visual range? You probably lose your model
Also, looking at the system in that link -- it's *mondo-expensive*.
You get a camera, laser-cut ply camera-mount, receiver and some batteries.
No goggles, (apparently) no head-tracker, no hi-gain antennas.
It's certainly not a cheap way to do FPV.