I heard some Falcon LS3/5As at Cranage last year and they were just staggeringly good on classical. Sugden class A upstream and some fancy stand sub units, which I wasn't entirely convinced by. The thing that knocked me out was the string sound on some obscure Japanese SACD of Saint Saens Organ Concerto (2nd movement), just wonderful. May well be the best strings I've ever heard from a hi-fi system. Annoyingly I've had no luck tracking down the SACD, and I've now forgotten what it was! They later stuck a late period Donald Byrd soul-jazz CD on and that worked a lot less well for me, though I have a feeling it was the subs tripping up, not the LS3/5As.
I have a feeling that I've dialed into the differences between the LS3/5A and 149, different positioning requirements aside. The former goes all out for mid-band tonality and has a truly beautiful, neutral and open mid, the 149 retains rather more dynamic punch and grip, goes deeper, but does so at the expense of the tiniest hint of B110 upper mid 'bite' (which you can largely tune out with a nice tube amp IME). The 149 is way, way closer to an LS3/5A than a Kan, but it is on that path. I have a feeling that if your musical taste is wide (as mine is) the 149 is the best of the three as it can do classical, jazz, rock, electronica, even reggae pretty damn well, wheras the 3/5A doesn't seem that great outside classical and acoustic music (where it is stunning), and the Kan needs to avoid all that and stick to rock, pop etc. The 149s can pull that Quad ESL imaging trick off too where they just seem to be in the room but have nothing to do with the music, you can look right at them and no music is coming from them, it is all above, below, behind, in front etc. I get the impression the 3/5As can too, but I've not had a pair at home to compare. I do think the 149 cab is special though and I'm amazed no one has copied it.