Great! Lots of nice new features that are all quite useful. Generators, for example, are something that I've always missed in Icon. And the set data type is also often very practical. And of course you're happy to take the runtime optimizations as well. There are also mountains of smaller syntax niceties included, not really important stuff, but pleasant when writing programs, simply because it looks nicer in the source code.
Particularly cool, of course, is the better OS X support, with direct integration of Cocoa!