Interesting thread. For instance I came across an old(?) post where Danny compared his N2X favorably with the Usher Be-718, with some advantages even. I can't help but think that the N2X drivers - as good as they may be and as tricked out as the crossover may be - are nowhere near as good as the 'world class' Usher woofer and tweeter. And yes I am going off the measurement work done by different folks at places like TechTalk, etc. but since Danny designed both I think it would real interesting to understand what facets make such seemingly incomparable designs comparable.
I ask partly because I just got the Usher 8948A and Usher 9950 to make a 2-way, and was surprised to come across Danny's comment re N2Xs! Maybe I made a mistake!
The woofers are fairly different but very comparable. The M-156X woofer has an XBL^ motor design that gives it an edge in the lower end. However to realize that edge that woofer needs to be in a optimal ported enclosure rather than the small sealed enclosure typically used to build the N2X model. The M-165X is a higher Q design that needs more air space, but that increased air space is what allows it to play down to a -3db that is below 40Hz. The Usher woofer just will not do that.
Another advantage that the M-165X woofer has is the polymer frame. This non-resonant design doesn't ring or transmit resonances to the front baffle like other frame types.
The Usher uses a little bigger voice coil that that does not make it sound better or worse than a smaller one. It's just a difference.
Both use a paper cone and have very similar sound to them in the mid-range. Bot are very good in that regard.
Both tweeters are very good, but my edge goes tot he Neo tweeter. It just has a more natural sound to it. It has great detail levels without being harsh. The spectral decay is pretty clean too. The Neo tweeter can also be crossed a little lower as well. The Usher tweeter has a great sound to it and nothing to complain about, but I'd say that it could be a little picker in regards to electronics. Anything up stream that is harsh or bright might come through that way a little more with the Usher tweeter.
Crossover parts used in those designs are about the same. Both use Sonicaps, Mills resistors, and Erse inductors. And both were voiced about the same by the guy that designed the crossovers (me

).
The N2X does come with tube connectors though, while the BE-718 inserts some rather larger binding posts into the signal path. So the N2X has a big edge there.
Also keep in mind that all of the tricked out BE-718's have been sold. All of the newer ones have gone back to the cheaper Chinese made crossovers and the performance is way off from the version that won all of the awards.
I think I have had two others do A/B's with both speakers and they also confirmed them to be pretty close. I think one guy wasn't interested in getting rid of his Usher's to build a pair as it was too much of a lateral move. But the other guy did mention that if he had known about the N2X before buying the Ushers then he wouldn't have bought the Ushers. He would have built an N2X kit.
Keep in mind too, that some people are just not going to build a kit, regardless, and some people are just not going to pay retail for a pair of speakers, regardless. So each of them fill a different niche.