Do you use a netflow analyzer?

I'm in my first job as a network admin and I've had the fortune(?) to inherit a neglected but configured and connected Riverbed Cascade Express (Netflow analyzer). Doing quick Google searches and job searches it seems that Cascade devices aren't very popular. Being able to map flows has already helped me to verify problems in our network so I'm wondering why this is the case. This leads me to a few questions: Is there a much more popular brand of Netflow analyzer or do people just use Wireshark? Are netflow analyzer appliances used in most large networks? I'm primarily interested in knowing if this is a valuable skill to develop or if I'm missing some obvious alternative.