I had used Colasoft Capsa years ago to find problems on our network. I see they now have nChronos which allows historical network analysis. I have been looking for something to be able to monitor our internet connection to see if and when we need a larger pipe. This product does the analysis by looking at actual packets instead of getting a summary feed from the firewall. I don't know that I need a technical explanation of why one way is better than the other.
I am interested in knowing if you have used the product or evaluated it and decided on something else.