Intercom: IntelliVox vs. ENRI

My current intercom is a Pilot PA 400 4-place portable.  I have used it for the
last 7 years and it works well for its price.  It works with all mine and my
friend's headsets, has good volume.  Once the squelch is adjusted, it does not
clip the first syllable from every word. There is some very minor distortion
but radio communications are always loud and clear.  My only complaint is that
background noise comes through mikes when anyone speaks.  I only connect
headsets with occupants to the intercom, and most times only 2 headsets are
connected.  My reason is that 2 connected headsets would have only 50% of noise
of 4 connected headsets because the single squelch circuit opens all connected
mikes when the squelch breaks.

I read a lot of good reports on PSE 7000 audio panel and its built-in
IntelliVox intercom.  Most reports say wonderful thing about its intercom.  The
spec sheet says only the spoken mike is open, therefore noise is reduced.

If I update to a PSE IntelliVox intercom, can I expect a 50% reduction in noise
because only 1 mike will be open vs. at less 2 mikes open at the same time on
PA-400?

I do not need a new audio panel, and I prefer portable to panel mount intercom.
 How does PSE's Aerocom III portable intercom w/IntelliVox compare with its top
of the line 7000's intercom?

FlightTech also makes a 4-place portable with its electronic noise reduction
(ENRI) intercoms feature.  My understanding of ENRI is that all mikes are open
at all times and there is no squelch circuit, but the ENRI electronically
reduce all background noise from all mikes at all times.  Isn't it a totally
opposite concept to PSE's IntelliVox design?

Has anyone used FlightTech's ENRI product?  How does it compare with IntelliVox
and regular intercom with squelch?

Thanks for any comments,

Robin Hou