I recently had a task that involved a 500G file. This fixed length file needed to be flipped or pivoted based on the content in certain fields. My first attempt at this was taking from 6 to 7 days, so I decided to give this module a try and got it down to a little over 2 days - amazing results! My only problem was understanding some of the documentation, which was probably because my programming orientation is more procedural than object oriented. But once I got some help from someone more knowledgeable, everything clicked into place. This is a great module!!
You've got to hand it to John McNamara. When he takes over the maintenance of a module, he goes all the way and doesn't hold back. I remember the very rudimentary documentation this module used to have under the old author. The documentation is MUCH BETTER now! The author of Spreadsheet::XLSX should take notes from John.
I'm having problems with extracting XLSX dates. The default underlying date number is useless to me. I'm sure there's a simple way to get the formatted date, but the sparse and cryptic documentation doesn't help.