Complexity
Part of this evaluation process should consider the complexity of the report you want to create. Here are some factors to consider:
Spreadsheet:
Easy -- Raw formatting
Medium -- Basic formatting
More difficult -- Charts, PivotTables®, graphics
Type of data:
Easy -- Part level
Medium -- Process and Operation Level
More difficult -- GCD Level
Availability of data:
Easy -- Already available as output in UI
Medium -- Can be calculated from available output
More difficult -- Needs to be custom-defined (probably for multiple processes)
Note: In general, if you can see it in the UI, you can access it for a spreadsheet report. However, you may encounter situations where this is not true. If you do run into this situation, please file a support ticket explaining what variable you cannot access from XML that you can see in the UI.