Exchange 2010 entered the Extended Support phase earlier this year. Basically this means that only security updates will be released to all customers. New and improved features will no longer be added and non-security bugs will be not always be fixed.
Exchange 2010 is a little bit special because it's currently the most widely deployed version of Exchange. And why not, the HA model with the DAG works like a charm, the product is stable and mature and has all the features you can think of. Of course the web interface is looks a bit outdated but it works very well.
The question is if and when customers should upgrade from something that runs pretty well. There is some similarity with Exchange 2003 in the Exchange 2007 and early 2010 timeframe, the software was outdated but it worked very well. This is why so many customers kept running Exchange 2003 until and past the end of Extended Support phase.
Very interesting is this little remark at the bottom of the announcement on the Exchange team blog:
Update Rollup 10 is the last scheduled release for Exchange Server 2010. Both Exchange Server 2010 and Exchange Server 2007 are in extended support and will receive security and time zone fixes on-demand on a go-forward basis.
So if you're running 2010, now would be a great time to start planning your upgrade to Exchange 2013, which is rock solid with the 9th CU released today, or Exchange 2016 which is scheduled for release later this year.