I've previously used Sizmek as our ad server, RFP/Proposal process manager, and reporting tool. Sizmek created a seamless transition from one step to the next, is user friendly, and dynamic to allow the user to do whatever they need. I love Sizmek.
Smart Planning - this is the tool that provides a process for RFPs, Proposals, and Final IO issuance. This tool was great not only to facilitate these processes, but housed all of these documents on a platform that anyone can view at a later date, prevented errors, and cut time in evaluation and implementation
Reporting - the reporting interface is very user friendly and can pull whatever you need. The export is easily made into a pivot as opposed to being formatted, and made our analytics timeline more client-appeasing
Support - the Sizmek support team is AMAZING! Very responsive, helpful, and timely.