Hi !

In my experience, if you process a lot of nodes into your array, is better "Process Private Globals", because it can use disk resource after complete all the RAM resource asigned to the particular process, like a normal global. In the case of  "Local Variable Arrays" you only use RAM.

If you don't need many nodes and your nodes save a small data, is better "Local Arrays". But if you have a lot of nodes and each one save large data (like xml content or csv file ) is better  "Process Private Globals".

Best Regards.