One company insists that short wave should not be used for indoor spaces and others are quoting using short wave.
The spread of Infrared on the EM spectrum is huge.
It is worth confirming that you are comparing heaters that are like for like.
Generally, the shorter wavelength heaters will use a tungsten filament in a quartz envelope, and will glow orange.
They provide instant heat, will warm people directly, but provide very little heat to the space.
Hence, useful for outdoors, or very large spaces where you can't hope to warm the whole room.
The direct heat can also become uncomfortable after a while (think what it would be like having the sun shining on the back of your neck for a couple of hours!).
The longer wavelength heaters won't visibly glow. Also, the longer the wavelength, the more heat they will add to the room.
If your hall is really large, then short wave heaters may be better.
If you want some heating of the space as well as the occupants, look at medium to long wave heaters.
I hope that makes sense