Kingsoft Office has better supporting of Microsoft Office than LibreOffice. But it's annoying every time when new release published to download and install it manually.
So, does Kingsoft Office Official PPA exist?
No. You need to download the debian installer file each time. WPS does not have an update feature. And since it is closed software it will not end up in the repositories since there license is in violation of any of the values Ubuntu stands for.
Please read LICENSE AGREEMENT OF KINGSOFT OFFICE FOR LINUX COMMUNITY VERSION (also called WPS OFFICE FOR COMMUNITY VERSION) thoroughly. Their license claims you can repack it but several other restrictions make it impossible for anyone to make a PPA: for one how are you going to prevent a North American to download from your PPA?
There is an easier way, through Ubuntu Software Center.
Once you've installed Kingsoft, in shows up there.
If you download the new version and double-click the download, the Software Center is activated en gives the possibility to upgrade. Just click on that button and there you go.