None of these three tools will be unknown to former users of Microsoft Office, and since the interface is practically modeled the same in all three cases, the quality and number of features offered are the same. While if you notice a difference in the performance, it is because Kingsoft Office is much lighter and will open your documents with surprising speed.
The three applications also are compatible with any 'doc', 'xml', or 'ppt' file, and you can save everything you do directly in one of these formats. Though of course, it also has its own native format. Also, it is possible to export documents directly to PDF format.
Another interesting tool included with Kingsoft Office is one that will allow you to encrypt important files in a way that they can only be accessed with a password.
Kingsoft Office Suite Professional 2012 offers everything necessary for the regular user to complete their work: a tool for text editing, one for spreadsheets, and one for presentations.
30 day trial.