lots to consider

- which is in best condition? new sails for either can be more than the cost of the boat

- with the daggers the 5.2 will point better, important in restricted waters

- will you tow it, or leave it on the beach rigged? if towed the prindle has less bits and is a little smaller so should be easier. check the trailer well

- will you race it? the nacra should be able to be sailed a round a course faster than a prindle or hobie16

- do either of them come with traps wires and harnesses?, you'll probably want to sail with them in a year or 2

- with a little work an old 5.2 can almost look as good as a new f18

- will either seller take you out on a test sail?