In my opinion, I think you should stick with your version. Even though I own a copy of version 10, I still use 7.2.

You see, Equis hasn`t really changed to much between version 7.2 and version 10. The biggest change was to the system tester however, this still has a couple of flaws and I use an alternative method to back test systems. Read about it here:
--> http://www.meta-formula.com/Metastock-TradeSim.html

In the newer versions of MetaStock there are more pre-programmed explorers, indicators, and expert advisors. But I think you should really design your own anyway. If you'd like to learn how to design your own profitable formulas you might want to get yourself a copy of the Metastock Programming Study Guide: http://www.meta-formula.com/Metastock-Programming-Study-Guide.html

So in short, in my opinion, stick anything from 7.2 onwards. There`s no need to upgrade!