Mike, I can answer your last question.
Biggest difference: Veeam Monitor is a standalone application, while nworks is a plug-in into your existing enterprise monitoring framework.
Functionality and feature wise, Veeam Monitor is shifted towards lower-level VMware Administrator responsible for monitoring and maintaining group of ESX servers. Veeam Monitor has pretty unique functionality to ease the actual low-level ESX performance troubleshooting: event correllation, guest process drill-down etc. It also has flexible built-in reporting to notify administrator about the issue before it starts affecting the users. Good reporting and trend analysis to watch your group of servers and be aware on upcoming bottlenecks.
Now, nworks solution is shifted towards providing insight on all VMware infrastructure to the enteprise monitoring team instead (the only way to provide this is to plug into the existing monitoring framework). So now enterprise monitoring team can get notified and see the problem no matter what server in what location is affected, see what applications are affected (new in 4.0), refer to the built-in knowledge base to better understand what is happening with ESX or specific VM, and dispatch the corresponding ESX administrator with recommendations on how to resolve the issue.
So both solutions complement each other very well.
Hope this helps!