Models? What did you listen to? Break-in & electronics make a huge difference. I have no idea what models you listened to, but, I can tell you that I have heard N800's sound good and bad depending upon the electronics, amount of break-in time, and setup. The Nautilus line seems to need at least 200 hours of break-in and the more current the merrier.
My own experience is that Wattage is not as important as the ability to deliver large amounts of current. The change in my system from a 125 W/per channel to a 200 W/per channel had more to do with the new amp's ability to deliver current and it made a great difference. I probably never use more than 10 Watts continuous power at any time, but, you CAN hear the difference with the higher current amp. No compression in the bass or limits in the high-end.
Using Levinson electronics may not be optimal with the Nautilus line and is no guarantee that they were driven correctly. Why not condemn the electronics instead of the speakers? Or, perhaps better yet, condemn the person who setup the system as not understanding the requirements of the speakers - as being terminally "mid-fi"?
Lastly, the difference between speaker sound with my B&W N802's from day one until now is unbelievable. The "honk" & "sizzle" is gone, bass response is greatly improved and the speakers make a large sound stage. B&W will tell you that setup is also important and you must play with the toe-in, etc.
It's easy to setup speakers incorrectly, drive them incorrectly and then blame the speakers. It's a chain and if there is a weak link or incorrect equipment choice, unfortunately, the B&W's will show you that.