It beats downloading other software, having to source an extremely linear mic (like the Berhinger) and then having to run it through a mixing board because the mic requires fantom power and then into your laptop. Trust me, it's worth it. I've already been down those other roads.
And the icing on the cake with this analyzer is that it measures down to 16 Hz.
The new Mag v4's don't do too bad.
An F3 of 16 Hz isn't too shabby.