I like that it is easy enough for someone with no programming knowledge to get up and running quickly, without having to hire an expensive consultant or pay high licensing fees. It's also very flexible in terms of how you can configure your filter rules - there are many different ways to do almost everything! You'll need some technical expertise (and willingness) to figure out what options work best for you. The customer support from PureSight has been excellent so far. My biggest concern right now is the price -- we're looking at several other products that have lower prices than this one, but deliver better functionality. We use CSDK primarily as our anti-spam solution. As such, we've had good success blocking spam, phishing emails, malware, etc., while allowing email messages that actually contain useful information through.