So what did I do? the verdict: I went with the Hobie 16. The Nacra 5.0 was just not in good enough shape... I wouldn't have been comfortable with the buy.
The right choice. A well maintained Hobie 16 is always to be preferred over any well beat up alternative. I wou;dn go out to sea on anything that isn't well maintained.
You get a good time on the Hobie, no doubt. The discussions mostly centred on the assumption that the state of the boats were comparable. In this case it wasn't.
Best of winds and heaps of enjoyment sailing your Hobie 16 !
Wouter