I have the exact same question ... unfortunately I don't have the answer... perhaps like you I love the Alto, but I am not sure I can justify 17K for the speaker. On the other hand I could more easily accept the cost of the Diva, but I am not sure how it will compare. I am surprised that we have not seen any english editorial reviews yet, since it has been released.
Incidently, for all it's worth, I posted a similar question on audioasylum and got one negative response:
http://db.audioasylum.com/cgi/m.mpl?forum=speakers&n=156397&highlight=jmlab+diva&session=
I guess another possible consideration could be the limited edition 25th Anniversary Electra Be 937, which uses a modified Be tweeter (same dome, but different magnet etc). Perhaps, this will be another way to get closer to the elusive Alto without spending 17K.
Incidently, for all it's worth, I posted a similar question on audioasylum and got one negative response:
http://db.audioasylum.com/cgi/m.mpl?forum=speakers&n=156397&highlight=jmlab+diva&session=
I guess another possible consideration could be the limited edition 25th Anniversary Electra Be 937, which uses a modified Be tweeter (same dome, but different magnet etc). Perhaps, this will be another way to get closer to the elusive Alto without spending 17K.