Question: I run Nagios 2.11 to monitor my servers, should I upgrade this to the latest version 3.2? 

I am very happy with nagios at the moment but wonder what the benefits are to upgrading it and could it be easier to configure and more checks. Would my exisiting configuration files work with the newest version?

Any thoughts on this subject grately received.

Answer: 
You will need to modify at least some of your configs when going from v2 to v3. Why not read the changelog and see if there are any changes that to you justify the upgrade. I see no sense in upgrading unless there is a real reason to do so (either features or security).
Almost always upgrade comes with problems. Usually you might get performance benefits but be sure that as with any other software you will spend day or two fixing newly found bugs and quirks. It's only upto you if you have spare time to change :)

Personally I would consider upgrade in your case (it works but Im curious) only if you bump into security issues that could compromise your host.