LCR-15s are actually my favorite speaker from Von Schweikert next to the VR-4jrs.... but that's another subject all together....
I have not heard the NHT's.... I keep meaning to set up a listening session with them, but haven't gotten around to it... I made a promise months ago that I would do it.... but haven't as of yet....
due to a PM request, my thoughts on the LCR-15s after having lived with them for quite some time and compared them directly with the other VSA models, a multitude of models from Usher Audio, and also Phase Technology's Premier Collection line....
first things first... the LCR-15 is an extremely easy speaker to drive... nice, flat and high impedence curve. I know several people using them with single ended triode amps because they are such a benign load and reasonably efficient.... receivers will have no problem driving these speakers to insane volume levels. The LCR-15 will take 500 clean watts and not break a sweat.... but it needs very little to work in a reasonable environment and any of the major brand receivers will power them well... however, this is such a high end speaker, that no matter how much you spend on front end equipment, they will not be the weak link and will reveal improvements you make in the source equipment.... I've driven them with everything from $300 receivers to $12K monoblock amps....
a stereo pair of LCR-15s is a definite step up in performance from a pair of VR-1s... Even though they use a smaller midbass driver, they go a little bit lower than the VR-1s and have even faster transient response and more detail in the bass they do reproduce......
What you get is incredibly clear, transparent, but extremely smooth, effortless and musical sound. The VSA stuff is incredibly good off axis, mostly because of the crossover design. So the speakers will sound just as good tonally in many different parts of the room, both on and off axis, above and below the tweeter plane.... They will also work, and actually prefer to be spaced further apart than most speakers. They throw a tremendous image, completely disappear, and have a lifelike, eerily real sounding reproduction of vocals and piano. They're just a touch on the warm side of completely neutral.
Don't let their size or driver complement fool you. albert has squeezed some serious boogie out of these speakers and they will rock with the best of them. They are extremely dynamic if called upon and make one of the best center channel speakers I've ever heard for anywhere even close to this price.... you can search through the archives here for reports from people who have replaced some rather exotic center channels with an LCR-15.. all were apprehensive that it wouldn't have enough this or that... everyone came away impressed and happy that they took the plunge and bought one...
The Phase Technology PC3.1MKII is a much warmer sounding speaker. It gives up a bit of off axis response to the Von Schweikert LCR-15 (but then again, virtually every speaker I've ever heard gives up a bit of off axis performance by comparison). The Phase Techs have a LOT more midbass punch than the VSA's, they go deeper and they mask bright movie soundtracks better.... the 3.1MKII's are an infinitely listenable speaker.. you can listen for hours upon hours and never get fatigued. They don't have the same realness factor to them compared to the LCR-15, but are still a tremendous speaker that I use as a reference and have a setup in my personal room just because they are so good.... great looking speaker too, and built very very solidly...
If you're looking for warmth and extreme dynamics, look no further than the Usher lineup of speakers.... worth every single penny of the asking price and then some....