I own a Legend, but don't own a Nox.
The exact same question has been asked numerous times on various Facebook metal detecting sites, and I've seen at least 100 replies to this question. Of those respondents that own the Nox and Legend, I'd estimate that at least 95% of them said they prefer the Legend.
The Legend matches or exceeds the Nox's performance. However, performance isn't the only factor that should be considered.
The Legend is not only much cheaper to initially purchase, but it's accessories like coils, pinpointers, etc, are much cheaper as well. Also, the Nox has thin and weak coil ears and a cheap, wobbly shaft. Most who purchase the Nox, purchase those two items when they purchase a Nox, which of course, increases the initial purchase price.
The Legend also has far superior build quality compared to the Nox. Again, the Nox has a wobbly shaft, weak and thin coil ears, and well known pod leakage problems. It's also important to keep in mind that when Nokta makes a mistake, or a problem is discovered, they fix it. Minelab on the other hand, did nothing to fix the serious Nox build quality problems.