You no longer have to grab a test version of Chrome to try push notifications for yourself.
Google has released the finished version of Chrome 42, which lets websites send you alerts (with your permission, of course) whether or not the browser is open. You can get breaking news, for example, or find out when someone outbid you in that antique auction.
The feature will be more than a little familiar to Safari users, but this is platform-independent – you should see it in Linux and Windows, too.
There aren’t any other conspicuous improvements to Chrome, but Google is promising lots of under-the-hood performance and security improvements that should make your update worthwhile.