If you have ever used Microsoft Office, then you might agree its one of the best commercial Office software suites available. I want to point out I make a distinction when I say "best commercial Office suite", if you're looking for a free office suite check out LibreOffice. I will note LibreOffice formerly part of OpenOffice, but it's a long story, but these are now two separate projects.
Although to come back to the original topic, the problem with Microsoft Office was that it felt too expensive for the home. For example, the current version of Microsoft Office Professional lists for $399 (MSRP) per copy. Although, if you purchase an Office365 subscription, you can get it for 5 PCs (or Macs) in your house for $99 a year, plus any updates. There is also some additional extras (like extra SkyDrive storage and Skype minutes every month), but check out the offer for more details.