I've always liked great soundstaging and a wide sweet spot in terms of tonality, so virtually all my speakers have had that feature (including of course the MBLs I owned until recently - and the Waveform Mach MC monitors I just sold were insanely good for not seeming to have a sweet spot tonally, and for imaging).
My current Thiel 2.7s with their concentric drivers and my Joseph Perspectives (steep crossover) both sound very even out of the sweet spot.
When the tone of a speaker changes obviously when I shift at all it bugs me somewhat. It reminds me of LCD tvs and rear projection tvs, especially earlier ones, where the image shifted in contrast and color if you moved out from a central viewing point. Hated that. (Which is why I went plasma in the early flat screen days).
Still, I think I'm actually less dogmatic about demanding a wide sweet spot at this point. Mainly because no matter how wide and even the dispersion, there's still only a narrow spot...really only one....where everything locks in and that's the one I'm going to sit in anyway.
I do have friends and guests who like to listen to the system when they come over, but I give them the sweet spot.