Main advantages - less resource hungry, more stable, more secure, a huge
and constantly expanding range of FREE applications that will (or at
least should) do everything you want/need, a very friendly and
knowledgeable community who will help you no matter how daft you may
think your problem is, vastly cheaper ;-)

Main disadvantages - poorer (but improving rapidly) hardware support,
poor support from the commercial software houses (but this can be
overcome to some extent by running Windows programs within Wine)

I switched from Windows to Linux two years ago and have *never*
regretted the move.