N-Stealth vs. Nessus

[Luman]

Hi,   I came across N-Stealth scanner, and I’m wondering what’s the difference between Nessus and N-Stealth? From the general presentation in their web site I feel it is more designed for web servers. But Nessus can scan web servers too. Thus, do you know if the vulnerability tests provided by N-Stealth are included in Nessus?   Best Regards, Luman