It is a prerequisite from Cisco that you have one of their product specialists for the deployment. You can't build the solution without assistance. I think that this is due to the cost of the solution, and hundreds of people have had a bad experience.

We implemented directly through Cisco. We had a good experience with them. 

We used a team from Cisco.

We do all our own deployments so there is no need for a vendor team. However, it is not recommended that end-users install this without prior knowledge and consultancy.