The Legacy Whispers are a rare breed - a dynamic dipole. To the best of my knowledge, the only other dynamic dipoles out there are the Audio Artistry line and the Gradient Revolutions. I've never heard the Whispers, but I'm fond of the Audio Artistry speakers, and I've chosen to be a dealer for Gradient. I've also designed and built my own dynamic dipoles, and own and sell full-range electrostatic dipoles.
I've never heard the Whispers, though I've heard a few other Legacy products. So I'm not qualified to comment on the Whispers, but I can offer a few comments about dynamic dipoles that might be useful.
The strength of a dipole bass system is its superb pitch definition. The bass notes decay more quickly and naturally. There are no distracting cabinet resonances, and the dipole's figure-8 radiation pattern puts significantly less bass energy into the room's resonant modes (5 dB less to be precise), so there is less room-induced blurring and coloration. In fact, the smoothest in-room response Stereophile magazine ever measured was from a dynamic dipole system, the Gradient Revolution, in 1997. Using 1/3 octave pink noise, the Revolutions measured plus or minus 1.3 dB from 32 Hz to 10 kHz - in a real room!
The drawback of dipole systems are limited low bass extension and dynamic range. A dipole system has to move from four to maybe sixteen times as much air as a conventional system (depending on baffle size and desired low frequency cut-off). This means large drivers, and lots of 'em, are needed for decent bass. The tandem driver arrangement of the Whispers is an ingenious way to pack an awful lot of cone area into a manageable size.
In my experience, a really good box system has better bottom-end impact than does a really good dipole system, whereas the dipole will have better pitch definition. To me, being able to effortlessly follow every nuance of the bass player or drummer's work is worth losing a little chest-thump. As is being able to tell the viola from the double-bass. Assuming the Whispers are well executed (and I'm sure they are), they should give you the kind of articulation in the bass that you're used to in the midrange. But more important (to me at least) is the things they won't do - namely, ruin the illusion with cabinet resonances, midbass thickness, and room-induced overhang and blurring of the notes.
I would be quite surprised if the Whispers had the bottom-end impact of the Watt/Puppies. But I think the Whispers will outperform the Wilsons in bass clarity and articulation. I couldn't speculate on the midrange and treble without hearing the Whispers, but Lgjg is quite experienced and his opinions are not just the ravings of an enthusiastic owner (or, in this case, former owner).
By the way, Ljgj, you know one of my Revolution customers. He's the gentleman who did the Quad 989/Martin Logan Odyssey transaction with you. He and I both enjoy your posts.