The only draw backs are the blades and cost of them... Research that - that said I love mine... I remember trumpeting it here once some time ago and was met with ney-saying....
However Bosch makes one now, and there is some interchangement of blade between the two with adaptors, and the Bosch ones apparently while cheaper do not fit the Fien. And there is one of the most usefull blade - metal cutting that Bosch is not allowed by patent/license to make...
And recently they added a diamond blade that I have yet to try.
FWIW - if you take a cheap scraper blade - cut some slots into bisiness end of it - even improve that some more by tweeking the blade between those slots to cut a kerf - what you then have is a great sheet-rock blade, leaving the wood blades for wood, and metal for metal.... It will also cut plaster like that as well. And it lasts quite a while...
Also if you look around you may find some black-market and other home-make blade info... There is also a file adaptor some people mention making use of...