Should I update from Joomla! 2.5 to 3.x?

From Joomla! Documentation

In most cases, probably not. Joomla 2.5 will continue be supported until December 31st of 2014 and you can update directly to Joomla 3 once it’s tried-and-tested thoroughly by other users. You can even wait until Joomla 3.5 which will be released in a year from now and still get a direct upgrade. The only reason you should update is if you need Joomla 3’s features or want to be on the leading edge.