The support means that canonical will still be providing security updates to the software, that means that packages such as apache2, php, and every package you have installed will still be receiving security updates. Note that security updates means fixes and paches for software malfunction, but it will not update a package to a new version, for example, if a new version of apache comes out, you will not get that installed unless you upgrade your ubuntu version.
This is actually good for servers, because if for example you make a web app that works great with a certain version of php, and a certain version of apache and mysql, you dont want those to be upgraded at anytime and possibly break something and give you a hard time trying to find the problem. But that doesnt meen that you will not get security updates for a long time (if you dont update) because if you use a LTS version, you will still be getting those security updates for 5 years without the need of updating.
From what i can say of the other side of the coin is that the upgrade from 12.04 to 12.10 is NORMALLY seamless (except if for example, some of your apps are not compatible with new versions of software as mentioned above). It appears it's not because here in askubuntu and most forums you will only hear the bad stories of people whose upgrade went bad and they'r seeking for help, because people who succeed normally dont make threads saying they succeed.
So to conclude, i'd recommend to stick with LTS version if your computer is a dedicated server which cannot afford to go down a few hours. If that server is also a desktop computer which you use for other desktop apps and you turn it off once in a while, and you always want to have the most newest possible versions of software, you might be good updating.