You should learn Excel 2013 if this is the version you will be using to follow-through with the lessons.
The first reason is that you would find it very tedious to work-around the changes in the user interface between Excel 2010 and Excel 2013 in the lessons. You won't, however, find any difficulties in applying your Excel 2013 skills using the older 2010 (or even 2007) versions.
The second reason is that Excel 2013 is vastly improved with many new features that you will want to use as soon as your office upgrades to 2013. You will (of course) miss the new Excel 2013 features and improved ease-of-use when using one of the older versions but you'll just have to live without them when you are at work for the moment!
2013 has some radical new features:
- Excel 2013 has been designed to work with Cloud Computing far more easily than with older versions (for more details see Essential Skills Session 8: Cloud Computing). Cloud computing provides a brand new way to share workbooks with any user (even users with Android or iPad pad devices, Apple PC users and users that don't have any version of Excel installed). Gone are the days when you had to worry whether the recipient of an Excel attachment had the right version of Excel to be able to even open it!
- Excel 2013 has a quite amazing and hugely useful new feature called Flash Fill that you can use to quickly complete tasks that were often very complex in Excel 2010 (see an overview of this in Essential Skills Lesson 2-21: Use Flash Fill to solve common problems). Most Excel 2013 users haven't even noticed this feature yet as it isn't at all obvious how it works until you've worked through the four Flash Fill lessons. But once you learn how to use it you'll wonder how you ever lived without it!
- The way you create charts has also been completely re-designed in Excel 2013 and it is now extremely easy to create and customize charts (for more details see Essential Skills Session 5: Charts and Graphics). Charting used to be very quirky in earlier Excel versions but now it is completely logical and intuitive.
- For expert users working with relational data (but this only be of interest to very advanced Excel users), Excel 2013 also brings data modelling, OLAP and Business Intelligence into the mainstream for the first time by incorporating many features from Microsoft's Power Pivot OLAP product into the standard version of Excel. Watch Session 6: The Data Model, OLAP MDX and BI to see Excel's ability to create OLAP Pivot tables that can summarize fields from multiple tables.
Of course there are many more detail improvements as well throughout Excel 2013 but the above four are the big ones for me. Any one of them would make the upgrade worthwhile but all four together make the upgrade to 2013 compelling.