I try to force myself to decide things quickly, probably too quickly given the nature of the hobby, where subtle differences in gear can emerge over time.... but too slowly given my other commitments :-o
I am noticing this morning how they both share the same family sound. Also I'm starting to think that the Sonatina II has a substantial edge in the midrange, probably because of that separate midrange driver with the big dome. As you say Jax the 17.5 disappears a little better. Does the 17.5 have more detail or just more apparent detail due to a less prominent midrange. I'm guessing more due to a newer generation tweeter but who knows. But the Sonatina II has plenty. I'm loving how easy it is to move the 17.5.
I'm engrossed in testing stands now for the 17.5 This is a new dilemna. Stands sound different.
Also I'm testing 4 ohm vs 8 ohm setting on my Cary SLI-80 with 17.5. The difference is similar to that on the Sonatina II but less substantial. Perhaps the 17.5 has a more even impedance curve? To my surprise I gravitate towards the 4 ohm setting. It sounds more gutsy. Perhaps that will change when I hook up the REL sub.
Art