I have my I18 on the "Ammersee" a lake in South Germany. The only F16 I have ever seen there over the last two years was one Viper headin' down South and coming back North with a broken jib :-/ I don't know where the boat lies nor who ownes it. The first close look I had on the Viper was in Texel this June. My area is Hobie dominated, then comes Topcat and then all the others but no F16's yet.

I think its a little bit like buying a car. If people have the choice most of them take the bigger engine (F18). Later they (me too) recognize the smaller one (F16)would have been the smarter choice. Especially if there is no real or big performance difference.