for customers Maestro will come out in a two three month or so , Nova Em litle bit later. It passed some time when I last heard alto, it was with top ayre and esoteric gear, valhala cables line.(much more expensive than speakers)but i remeber it has nice ,accurate and traditionaly to focal -warm sound(midrange bloom) Scala is much more dynamic sounding in midrange and treble and more three dimensional with better sense of space and most important is does not sacrife "easy flow of music".. the same wartmth is still here.
as for diablo- diablo comparing with scala not so dynamic=lively but its calm and smooth all the way no matter what record.
as for Isis, I DID NOT heard it , but i perfectly know the drivers and litle bit their enginiers xover implementation. isis should be more imediacy sounding and very good on audiophile female voices, on clasical works, other material it likely WILL be(unless isis will do revolution) be somewhat hard , cold sounding ,unless you using tube amps-they will round a litle bit that c173n midrange. if you like very trasparent and very dynamic,fast and lively but somewhat cold/sterile studio sound like midrange -isis may be a solution, if you like litle bit(still very good) slower smoother midrange .
as fow lows there wil be oposite- nova will be bullet fast real life like performance and way better in that respect than iris. if you in a clasical music nova will show what EM are capable of. iris in bass would be better on rock and electronic. I am prety sure, but to clear myself i DID NOT heard iris.