Google Docs & Spreadsheets (Beta) review
The spreadsheet module is similarly limited in terms of features. A large number of mathematical functions are supported, but the formatting options are poor. You sometimes struggle to get the borders you want on a cell or range of cells, and the list of available fonts is smaller than in the word processor. The formatting of values as currency, percentage and dates is also limited. The most disappointing omission, though, is that there are no facilities for graphing the data or producing PivotTables.
Google Docs & Spreadsheets has two unique selling points: 1) it, and your documents, are available from just about any computer with a fast internet connection; 2) you can collaborate with other users in the same document, provided you grant them access. If you need those features and can put up with the limited features, go ahead. If you need professional-looking documents or a sensible UI, you need to look elsewhere for now.