I had a similar dilemma recently. I ended up going from Magnepan 1.7s to 3.7is. ... I can tell you that the 3.7is are a big step up from the 1.7 - that true ribbon tweeter is sweet! The soundstage is bigger and deeper too.
@thewetdog59 thank you. Hearing good things on both of my options here. Also agree with @gormdane that I should audition, however I do not know how I would be able to pull this off. Would love too though, specially in my own home. That would definitely be ideal.