We've used a Barracuda 410 in our environment for a few years and love it. We migrated away from Websense (I believe because of cost, but can't remember exactly). We're happy with the 410 - it definitely blocks the sites our users should not visit, but also actively scans for malicious web activity which effectively adds another layer of protection in our security structure.
I believe we're paying around $400 annually for renewals.
http://www.barracudanetworks.com