Hi MBOUDS-
are you sure the H16s you are talking about are not from Hobie Europe?
I can only speak from the experience of my many sailor colleagues (we have at least 200-300 cats on our beach) who've recently bought H16s and TheMightyHobie18 SX. The TheMightyHobie18's dagger boards went bad right away, with the edges chipping off. 2 H18sx owners had their jibs shredded in less than 2 seasons.
Then there were problems with rudders on several new boats (both H16 and TheMightyHobie18). On another H16 the forestay screws ripped out of the front hull. Another guy's wing came off his H18sx, although he only had himself and a couple of little kids on the wing at the time (expensive repair, since it has to be welded back in). Then there were numerous other smaller, but nevertheless annoying quality problems, such as problems with sail shape (seems different every time, often with that annoying huge bulge), or razor sharp edges on that thing through which you thread the sail. Another boat owner had proplems w/raising the sail the first time, first he couldn't raise it because the sail edge was too thick to fit through (took 3 guys to hoist it), then it absolutely refused to hook in on top.
I could go on and on. In my experience the older Hobies were much better and more solid. Sail shape of the really old ones from the 1970s and 80s is much flatter, for example.
I found the relative simplicity of the Nacra much easier to handle.