The spreadsheet module is fine for simple calculations but don't expect a speedy response with a sheet of any meaningful size. There's also quite a lot of flickering as sheets are saved or recalculated. Even a small spreadsheet takes a couple of seconds to turn a simple formula you typed into a result. Charts are rudimentary, and only in garish, primary colours, and there are virtually no tools for editing charts short of changing the title or redrawing a column chart as a line chart. If you want to publish a chart, Google gives you a snippet of HTML to copy and "paste into any HTML page" - not very helpful, unless you're adept at editing raw HTML.
For presentations, Google Apps are barely adequate. There are 15 themes, all of which look tired and dated. With just six fonts to choose from and little control over the layout of the standard blocks, slides could quickly become boring and "samey". Inserting images means browsing to upload the image from your PC, or typing a URL to copy an image from the web, and then waiting to upload it to Google's servers before it appears in your presentation. Dragging a corner of the image to resize it then changes the aspect ratio, unexpectedly squashing or stretching the image. (You have to hold the Shift key to resize retaining the correct proportions.)
You can choose for bullet points to appear one at a time but there are no facilities for setting delays or saying how words, shapes or pictures appear. Importing a fairly simple Microsoft PowerPoint presentation mangled the bullets, lost all the transitions, animations and speakers notes and let the text run off the bottom of virtually every slide. It was unusable without spending far too much time editing it to fit.
The user interface for all the applications is starkly functional. There are a couple of menus and a row of toolbar buttons. Nothing fancy but quite sensibly arranged. You've not got many places to look to find the function you are after, or to find that it doesn't exist. It can however be confusing that the same command can be called two different thing on different menus; for example, "Change Row..." and "Modify Row Properties...".
Importing and exporting
Support for importing from and exporting to other packages is basic. Microsoft Office 97-2003 format (doc, xls and ppt) is catered for as are OpenOffice ODF files but Microsoft Office 2007's OOXML (docx, xlsx and pptx) aren't supported, nor are the translations particularly accurate. There are far too many features missing from Google Docs to make a good translation of even a moderately complex document. If all you deal in is plain text with simple formatting (bold, italic) and simple headings you can probably import and export documents successfully.
