Best monitor I've heard, by far, is the Intuitive Design Summit. Other monitors I've heard include Totem Tabu's, JM Labs Micro Utopia Be, and the Induction Dynamics S2 monitor (the S2 retailed at about $3000 the last time I checked). The Induction Dynamics Monitor is really special, and has a large, open, smooth and detailed sound. It uses a proprietary ("S4X Driver-Control Technology") fourth order crossover with inductively coupled drivers (their "brick wall" crossover, see footnote #1). I'm not sure, but they may be even better than the Totem Tabus. GREAT little speaker.
I'm fairly certain that the Summits are also the best speakerof ANY type--which I have personally heard--with the closest competitor being the Old, three box version of the Audio Physic Caldera being driven by about 7000 dollars of electronics, including Spectral products.(**See footnote #2). The Summits DEFINITELY sound better (at least overall) than any other floorstander I've heard, including Hales, Aerial 7 B's, Dunlavy SC IV's, Thiel CS 3-point..something, Totem Winds, Paradigm Studio 100 V 3's (which I owned for about a year or so), and Paradigm Signature S8's (which I auditioned in my house side by side against the 100 V 3's). There have also been some "dogs" which needn't be mentioned.
*FOOTNOTE #1: The approach taken by Induction Dynamics is essentially the opposite of a first order crossover, and may even be more stringent in terms of driver control than that of Jim Thiel, although I can't say for certain. On the Induction Dynamics website, they take great pride in pointing out their unusually steep crossover design.
{{Here's a quote: " S4X Driver-Control Technology delivers a virtually instantaneous roll-off after the crossover point, the quickest slope in the industry. This fast-acting "brickwall" crossover slope exceeds 30 dB/octave within one-half octave of the crossover frequency. Most crossovers range from 6 to 24 dB/octave and don't develop their maximum slope until the second octave."}}
All I know is that they sounded very, very good, and would appear to be a standout speaker in that class. Their soundstage did NOT seem constricted, and I say that knowing that the Summits and the Calderas both use a first order crossover (among other things, of course) to get their outstanding imaging.
**FOOTNOTE #2: It's close between the Calderas and the Summits, and it was a while ago, but I strongly suspect that the Summits would sound better in a direct A/B comparison based on my auditory memory. It's possible (but not likely) that I'd change my mind if an A/B was possible.