I don't feel the feedback given on them back a couple years ago when they were made implied they were anywhere near the same quality as any of those. They were based on Armalite's older receiver design - now the AR10B I believe - and used the same modified M14/M1A mags that the AR10Bs utilized. Once Armalite changed their receiver design to the AR10A to accept PMags Noveske stopped making the N6. Noveske's uppers wouldn't fit on the new Armalite lowers as a result of some dimensional changes with the new Armalite design. As rumor has it, Noveske went back to the drawing board in an effort to redesign the N6 into an SR25 compatible system themselves. That's the last I ever heard about anything N6 related. They still sell N6 barrels I believe.
Armalite gurus, feel free to correct me if any of the above is inaccurate. It's been a while since I've chimed in on the N6 topic...