op
my understanding (not personal experience, as i have not had the older spatial models) is that the new sapphire series uses new drivers, and in particular, the upper freq driver such that the speaker's resolution and 'liveliness' is enhanced greatly versus the older series - some will bemoan the new speaker sounds too hot up top... it does smooth out considerably with break in - but that is the main difference
others say that the bass response is also better, but i think that is a secondary level of difference, more difference up top and thru the upper midrange
i suspect at the end of the day, system matching could get both speakers to play very well, subject to personal tastes on a smoother versus a more visceral sound