Its unfortunate that you are stuck in that boat, we had looked at the ProductPoint for a few customers and decided against it, (Lucky)
We did go through and implement Windchill Intralink 8-9 for a couple of the companies and it worked fine. When you really take a deep dive into the configuration you have a Tomcat Apache and WindchillDS as extra components. compared to Intralink 3X. With your number of users, intralink is fine. We even did one PDMLink implementation with 3 users.