And mutation testing... which in my opinion is just way easier to do and more mentally straight forward. Plus you get the satisfaction is actually knowing you're DONE, unlike PBT where you just give up after a certain amount of CPU time has passed.
I also consider mutation testing to be in a different domain from property based testing, as mutation testing is some kind of metatesting instead. PBT is a 'regular' testing technique. This means that they are in fact complimentary, for example by using PBT to check mutants. (Although mutation testing does seem to assume a sort-of 'fixed' test set, but you can also fix a test set with PBT by e.g. explicitly setting a seed and test count.)
Have you somehow managed to overcome the maxim that "Testing can show that defects are present, but cannot prove that there are no defects" ?
If that behavior is wrong or not it can't say. For example it can't detect that the code needs MORE behavior! Some if-statement or loop that was never written.