jclouds 1.6 represents 7 months of refactoring to essentially "reset" the project 4 years after its founding. The goal was to do less magic and be easier to code and troubleshoot.
No doubt, we've added new apis, including ones from OpenStack, Rackspace, AWS, DynECT, and UltraDNS, so if any of that interests you, move on to details in the release notes.
Most exciting is our move to the Apache Incubator. Watch out as details will unfold this week as we progress to our next level of open source!
In the mean time, update your jclouds to version 1.6.0 and let us know how it works for you.