Salt Lake County does a great job of leveraging third party products and partnerships. Their PowerPAC includes full integrations with both Bibliotheca Cloud Library and Overdrive eBooks. The County Library takes great advantage of the Polaris integrations available from ChiliFresh (including bookjacket cover art).
SCCCPL migrated to Polaris from a library system they created on their own called Listen2000.
TRAC was one of the first Polaris consortia covering such a wide geographical area. TRAC has always been a progressive site, particularly given the challenges of serving a multi-type, multi-system consortium spread across a large region.