We deployed SMACS (Stack8) approximately 1.5 years ago. From day 0, we have been pleased with both the product, and with support. Like many Cisco UC customers, we needed a product to assist with the daily moves, adds and changes. We decided to go with Stack 8 for two reasons:
1. One of our peer companies was using SMACS and they highly recommended it.
2. Out of the couple of products we evaluated, the Stack 8 demo sold itself. The engineer that performed the demo was very knowledgeable and everything within the demo worked exactly like it should.
Since deploying SMACS, I honestly do not think we could live without it. Using SMACS for provisioning has dropped the configuration time to approximately 1-2 minutes per user (for a help desk level technician). This configuration time includes the user, phone and Jabber configuration. Additionally, support from SMACS has been very professional and they are always knowledgeable. We recently completed a Cisco CUCM upgrade from 11.0 to 11.5. When it came time to upgrade the SMACS piece, Stack 8 support assisted with the upgrade and the upgrade went very smooth.
I would highly recommend the Stack 8 product.
I hope this helps.