If you are starting a new project, by all means use Infinispan.  If you already use JBoss Cache, consider upgrading to Infinispan as this is where most of our focus and efforts will be.  There is a compatibility layer to help people migrate, although we recommend only using this if you (a) absolutely need a tree structure, or (b) only for a short time as a stepping stone.  You will find that Infinispan's Map based API performs much better.  In addition, we plan to provide migration guides and configuration conversion tools.