Comparing IDFs is certainly possible, but perhaps an easier way in DesignBuilder would be to use the Model Data Grid View tool. Generate the grid view of the data you want to compare then export it into Excel for direct comparison. This will give you a nice simple view of the templates and settings you've used without wading through all the detail contained in an IDF.

I can't answer for DesignBuilder specifically, but you can compare the two IDFs with a text comparison tool like WinMerge or BeyondCompare. If needed, you can use IDFEditor or Eppy to sort the IDFs in a consistent manner for comparison.