What are the disadvantages of using Google apps?

There may be language limitations to google Docs, where more commercial products are widely available, worldwide, in native languages.

google Docs is not robust in the commercial sense of a set of robust office products. Complex, obscure, infrequently used features are generally not available.

As well, if the google Docs servers are 'down' for any reason, you may not be able to access the files you need.