I have a pair of Omen Def Mk1b for 5 months.
In the beginning, right out of the box, I remember they sounded a bit "fat" for my taste. I was missing some brightness, some treble detail.
Then they developed week by week and I guess they will continue to change until they are completely broken-in. And all I can say by now is that the sound is amazing! I'm driving them from a push-pull 35W amplifier (Cayin MT45 Mk2) and I can never reach the 12h on the volume knob (at least in my apartment...). They are indeed very efficient and any low powered amp will make them sing.
Regarding the positioning, I never felt the need to be moving them around. Just got them in the selected location and then adjusted the toe-in angle to get a good stereo sound and that's it! They really sound powerful and detailed, it's a gorgeous sound. But I would't say transparent or neutral; they put some tone in the music, which is good for my taste.
And finally a word to those guys at Zu: They are top notch! I live in China and after auditioning the speakers in two different stores I decided to wait some more months (or years) until my budget could reach those speakers. But one day I found a pair in their website for half price ("preloved" section), mailed them and soon after the speakers were in my living room! They really like what they're doing and they take good care of costumers.
Anyway, I advise you to go listen to the speakers and then decide.