The first impression of the software is its uncanny resemblance to Microsoft Excel 2003. To get a sense of this look at the screenshot.
Kingsoft spreadsheet screenshot 
It is quick to load both the application and an .xls spreadsheet file. The menu structure has the same headings as Excel 2003, but there are less options on those menus. This brings simplicity of use, but also means that some features of the Microsoft product are missing.
The handling of .xls files is seamless and rapid and Acrobat (.pdf) files are also available directly. However, the overall choice of file formats is smaller than in Excel, and users of historical Lotus spreadsheets would have to use an intermediate format such as csv, or dbf, which is supported. The application has a reader for .xlsx files but no export facility. Whilst I am not sure why you would want to export files in this format, the import facility might be needed. It is currently in beta, and I confess I lacked the confidence to try it after my experience with .docx files. Most of the most commonly used features are present, including wizard like facilities for tasks such as chart production.
The most significant omission in this area may appear to be the restriction to 2-d charts. However, 3-d charts, whilst attractive are not the best way to display data, and have been criticized by a number of academic authors, including Anna Hart in Making sense of statistics in health care, so this omission may well be a blessing in disguise. The very useful Autosum and AutoFill features from Excel are reproduced here, as are a healthy range of statistical and analytical functions.
The inclusion of an inbuilt Google search facility is a nice touch, but less obviously useful than in the other elements of the suite.