I first met Jean-François Beaudin at the Boston Early Music Festival several years ago and had the opportunity to try his "modern traverso" of which I've subsequently purchased two (one at A=415 and one at A=392Hz). 

I've only ever played simple system flutes, and found that this new traverso to be nothing short of a revelation.  Its sound and playing qualities are closest to that of pre-1750 style instruments (a generous strong low register) though Jean-François offers many different styles of embouchures and head-joints to meet the needs of his customers.

The clarity of sound and balanced intonation particularly in the fork-fingered notes is a real delight for those of us accustomed to the one-keyed "period" traverso.  That having been said, it's not a "better" instrument, only a different interpretation of it which can offer possibilities not easily achieved with the earlier style flute.  The single biggest difference that will strike any player upon trying the modern traverso for the first time is that it has a much stronger (read-louder) sound than one is used to with a baroque flute.  This has come in very handy for me when I'm the only flute player in a large orchestra whose concern for my ability to be heard is not necessarily their first priority.

Jean-François's flute gives one a bigger sound but a very flexible one that can create sweet, clear pianos combined with loud, robust fortes.  To give one an idea of this, the volume one can create with this flute is more similar to that of a baroque or classical oboe.  Though I'm still an active performer on period-style, simple-system flutes, this new addition to the family of traversos has been extremely enjoyable to work with and also extremely useful!  I would encourage any player to add this flute to their collection.