I'll add my own comments, as I'm curious if people disagree as well.
I have had speakers similar to the Audio Physic -- I see the AP having more precise, yet for lack of a better word, static images. I don't mean lack of 3-D images, and want to be careful with the word static. I see the Klipsch's as having not as pinpoint images, though still good enough, but with more character, more aliveness -- I think of it somewhat as projection, like an instrument would in real life, vs. a perfect 'image'. From my experience, the Klipsch's have a more forward sound -- not in the negative sense that people use the word and with much larger images. Again, personal preference vs. right and wrong.
It becomes a matter of taste -- a word on the AP's and a lot of dynamic speakers like it might be 'refined'. But with the Klipsch's, you get this aliveness, something fun, something a little less 'tame', but which reflects reality more than reproduction.
I do agree that with most horns, decent horns, whether you're talking Klipsch's or extremely expensive well done horns, system changes are much, much more noticable -- give them the bad, and you'll get the bad. Give them to good, and you'll be amazed, but just be careful on knowing what your speakers and components can do, as its easy to place blame in the wrong places if you're not careful.
Everyone has different preferences, and most of the time they are very valid. Giant boxy speakers are usually equated with head banging, or with clubs, and not with refinement. That and I'm guessing that a lot of Klipsch's heyday was also around when solid state, and bad solid state, was being shoved down people's throats. The combination wouldn't be pretty, and I have to wonder if these two situations are part of why certain people have assumptions about Klipsch...from some time past, with some horrible system combination. Yes, they've been around forever, yes some models were designed and tested around a 2A3, but I'm talking about most of the public's perception, and not in audiophile land. Not the now referred to heritage line, but you will find Klipsch as a brand that an average consumer might be familiar with, and I have to assume that because they are so widespread, that a lot of people who have heard great reproduction, have also been exposed to some horrible, and horribly cheap combinations with Klipsch, and thus form a perception of the speaker itself. Granted there are people that don't like them period though.
Curious to hear people's thoughts, opinions, and experiences regarding -- they intrigue me because they have that ability to bring things to life, and yes, sometimes at the expense of other qualities we are used to being better in other speakers. Everything (or almost everything) has some sort of trade off. You can have something very 3-D, something very precise, but something that doesn't project like music and instruments do, and so it doesn't feel real. You can have something that is very exact, but projects little tiny images that don't equate with reality. For me, a lot of this preference also equates to the 'you are there' vs 'they are here' preference, what sort of music you listen to, and what type of recording you listen to primarily (studio vs. soundboard vs. live at a distance) You can also have something that has that 'life' but not all the buttoned up perfections -- it may help you to stop caring about, and focussing on the details, and help you relax and listen to the music.
Again, talking about frequency ranges, and detail is a lot easier than describing preference and music and what does it for you, so take all of the above as opinion and nothing more.