For years, Microsoft Office has been the champ of office suites, and it still is. I like it very much. However, that doesn't mean there are not free alternative. It's just that Microsoft Office is so much better and practical and was integrated into many point-of-sale systems so many people paid the $300 to get it.
Well unlike many other point-of-sale systems, our users have a choice, to decide whether they use Microsoft Office or the free Openoffice.
The choice depends purely on what you prefer. If you are a big user of word processing and excel spreadsheets, used to the Microsoft product and require much, then I would recommend Microsoft Office, mainly as I think it is better. If alternately you only write a few letters, a year and need only simple to moderate complex spreadsheets, then openoffice in most retail environments is fine.
Both are extremely good and solid products with all the basic office suite functions required. Both will do everything that most people require.
Both are getting better all the time so you can grow with them.
My recommendation would be if you do not have an office suite and feel the need to be able to do some word processing and spreadsheets try openoffice as its free. Use it with our software. Learn how to use an office suite. Subsequently if you decide you do need something better or its not working for you then switch to Microsoft Office.
Remember with us, you have a choice.