First off there are now five mics and the two stereo pairs seem to be both 90 degree XY.
As far as I can judge from the videos and the press release, on the front face there is an MS array comprising one forward-facing mic plus a pair of side facing mics back to back imitating a fig of 8 mic, hopefully all three mounted in a column vertically for phase coherence. On the rear face there's a phase coherent 90 degree pair definitely mounted one above the other.
You have at least five if not six or even seven output options - the knob on the top selects four options with the sub-options for MS dematrixing or not set in the display using the jog button.
- MS recorded from the front array dematrixed to L/R (two tracks recorded)
- MS recorded from the front array undematrixed ("Raw" they call it) with one track "mid" and the other track "side" for altering width in your DAW later, or in the unit (two tracks recorded)
- XY from the rear pair only (two tracks)
- MS from the front plus XY from the rear, mixed down in the recorder to two recorded tracks (stereo), balanced using the display and job button. Not a good option unless you don't have a DAW for post-production.
- MS from the front plus XY from the rear, unmixed and recorded on four tracks.
It may be possible that the last option is actually two options, whereby the MS array would be recorded either dematrixed or undematrixed (raw) onto two tracks, with the XY recorded onto the other two tracks. And, if you use the MS option with the side signal right down, you've essentially got a mono recording off the front-facing mic, which could be useful for interviews, and you could regard that as a seventh option.
For acoustic music in reverberant spaces these options should provide considerable flexibility, especially using a DAW after to vary the mix as required.