The biggest pitfall is that you might lose you Outlook .pst file, thus all your current Outlook data gets lost.

Check out http://www.chimpytech.com/backing-up-your-outlook-data/
for some advice on backing up your data, there are also some useful articles on moving, restoring, re-importing etc should you need to move / restore your .pst file.

You are also likely to lose any customisations you have made, so make sure you know how to re-create them again if necessary.

HTH

Neil