Moving an Excel spreadsheet as a file to any of the cloud services is a good idea depending on what you need to do.

Converting an Excel spreadsheet to a Google Doc is a bad idea. Google docs, to put it mildly is brain damaged. You will lose almost all of your functionality. Google docs barely remembers simple formulas and is basically an Excel spreadsheet with data-only in it.

Better still would be the on-line, free apps from Microsoft. Once again, they are not the fully-featured products, but they do most things most people need them to do.