I think it is best you get an inexpensive nacra 5.0 c.q nacra 500 or Prindle 16, hobie 16 at first. That is unless you are already a committed sailor and/or experienced sailor.
These boats are just so much simpler to figure out and as they can be had pretty cheaply there are less of a risk when you are still at the lower portion of the learning curve.
However if you have decided to jump in at the deep end and seriously consider the Nacra F17 then be sure to check out the Formula 16 boats as well.
www.formula16.orgWouter