We've now completed a number of PoCs in which customers compared Sametime Advanced to the capabilities of Instant Team Sessions and/or Instant Queue Manager.
It appears at first glance that ST Advanced has a low buy-in, but the feedback from the field indicates a high total cost of ownership over time. ST Advanced requires a minimum of five separate servers (and more likely double that number, if you require redundancy). Which also means you need the technical competency to maintain and manage all those servers - Websphere, Websphere MQ, Websphere Event Broker, DB2 Enterprise server, DB2 Net Search Extender - over and above your Sametime and Domino server.
For all of that cost and complexity, what do you gain? The main reasons to deploy ST Advanced are persistent chat, broadcasting, and screen sharing.
Instant Team Sessions provides comparable persistent chat capabilities, while Instant Queue Manager matches most of ST Advanced's broadcast features (the two exceptions are broadcast alerts and polls). Instant Queue Manager actually offers a lot of important functionality not available in ST Advanced: Support for both internal and external users via the ST Connect client and/or ST Links; intelligent routing of requests to the relevant subject matter experts; automatic issue escalation to improve first-call resolution rate; automatic metric tracking for management reports (eg, wait time, time to resolution, etc); and much more.
The best part is that you don't need to deploy any extra hardware or learn and maintain any additional technical skill - all you need is your existing Sametime/Domino environment.
Customers who have done the cost/benefit analysis are invariably choosing Instant Team Sessions and/or Instant Queue Manager over ST Advanced.
We are preparing a technical brief to help you make your own cost/benefit analysis. We will post new of its availability to this space as soon as it is ready for publication.