I will say this, the WebGate from Symantec if purchased a certain way, is one of the cheaper products out there, it can be had for a steal, especially when compared to IronPort.
Get the Protection Suite Enterprise Edition which includes the subscription to the webgate product, and pick up the appliance separately, and you'll have an extremely well rounded security platform for a steal.
There are two levels of appliances, one that supports 1000 users and 100Mb of bandwidth, and one that supports 10,000 users and 1Gb of bandwidth. It's a sliding scale too, so less users, you can have more bandwidth...