From what I have read about SQL Server Resource Governor, there really aren't any cons. I'm looking at implementing it into our infrastructure where we host websites as well as a management system plus reporting. The management system requires data to be loaded which has to be done out of hours because its quite resource intensive and has a knock-on effect to the websites. So, using the Resource Governor to split out the resources makes sense. Any thoughts?
Well yes and no. The biggest con of implementing Resource Governors is having your classification done properly. In most implementations of this concept I have seen you will need to have a significant period of analysis to determine the pool sizes and proper pool placement.
Normally the implementation of the OLAP(Reporting, Analysis) and OLTP(Like webhosting process) is split so that using the Resource Governor is not an issue since the reports may need to be run ad-hoc you don't want to have the "big boss" waiting on the data.
If you really can't do that then Resource Governor might be the way to go but I'd look at other solutions OpTier. They looked pretty good last I looked for a similar solution (though it was for Oracle)