What I appreciate about Jexcel is their numerous input methods (like dropdowns and checkboxes). DGXL does not offer these features at this moment.
Both Jexcel and Handsontable are quite excellent when it comes to the amount of features, but they do have the same downsides: their enthusiastic creators implement any feature that they can dream off, ingoring the effects on performance and a growing code base that gets more complex every time.
If you're looking to create a spreadsheet app to compete with Excel or G. Sheets, don't look at DataGridXL. If you're looking for the fastest and most reliable editor for 2D or JSON data sets, choose DGXL :-)