It [has been] a pleasure working with you. We truly appreciated the quality of the deliverables, as well as your professionalism and flexibility in adapting to our evolving needs and constraints.  Please share our appreciation with the entire team for their dedicated support throughout the project.  We look forward to continuing our collaboration.

On behalf of the team I would like to thank you for a fruitful collaboration and for all your work.  It is always such a pleasure to work with you and we look forward to more exciting projects next year!