I own this mic in your link. I enjoy using it a lot. I am more of a home audio enthusiast than a PA enthusiast. I use it to take IR measurements, which the software I use then provides a frequency response. The microphone is very similar is size/looks to my Behringer ECM8000. Although this seems to have a better response than the berry. The calibration from Cross Spectrum is very nice for my purposes, which desire +/-2db accuracy from 10hz to 20khz. Not many PA applications would have that kind of requirement, so not sure the calibration is so useful.
My only beef with it, is the length of the cable. It's 1.2m iirc. That's not so useful. Sure, you can get a longer cable, but I haven't done that yet.
I personally don't have a need for dual channel FFT. I can get phase alignment with an IR. Although it possibly takes me longer and I have to figure out the delay myself.
If there's anything you'd like to know about it, I can try and help.