Using xlCompare to merge Excel spreadsheets.

xlCompare has wide range of features to merge data between worksheets.
When you've got comparison report for workbooks you can use the following features to quickly merge data:
Difference Browser Toolbar:
This set of commands quickly moves data from one worksheet to another or deletes data from the sheet.
10 commands resolve all possible types of differences:
New row which has been added to the right workbook can be copied to the left sheet or deleted from the right sheet.
Row, which has been deleted from the left worksheet and can't be found on the right sheet, can be copied to the right worksheet or deleted from the left sheet.
Added and deleted columns has similar merging commands (highlighted on the screenshot). You can copy column to another worksheet or delete it.
Modified cell can be copied from the right worksheet to the left one or from the left to right. These 2 commands performs copy operations.
Select the range you need on any sheet. Press Ctrl+C or Ctrl+X (or use Copy or Cut commands from the Right Click Menu) to place data to clipboard. Then select destination range and press Ctrl+V (or use Paste command from Right Click Menu).
Select the range you need on any sheet. Drag it with a mouse to any sheet, place it over any range and drop. Data is pasted into destination range. If you move data inside one worksheet - xlCompare moves dragged range to new position. To create a copy of the source range you should hold Control key when dropping data.
Clear selected range:
Select the range you need on any sheet. Press Delete button or use Delete command from the right click menu.