The good thing is, for mere mortals such as myself, that Oracle provides a nice bullet list of improvements in Solaris 11. In addition, there are several people on the web who do actually understand all this stuff and who summarise it neatly for peasants such as myself.
The big focus seems to be two technologies-turned-buzzwords: the cloud (in normal-speak: the internet) and virtualisation. "Oracle Solaris 11 is the most significant operating system release of the past decade. With built-in server, storage and now, network virtualization, Oracle Solaris 11 delivers the industry's first cloud OS," said John Fowler, executive vice president at Oracle, "Customers can simplify their enterprise deployments, drive up utilization of their data center assets, and run Oracle and other enterprise applications faster all within a secure, scalable cloud or traditional enterprise environment."
Solaris runs on both SPARC and x86, but my guess is that if you use this stuff on a regular basis, you're probably already aware of all this and are already mulling over implementing Solaris 11 within your organisation.