> how many fails (at various levels) have we seen of these managers?
Certainly less than with using "0000" or your children/pet's name as your password.
But you're right, you have to chose your password manager with some care, many are chocolate teapots, others are downright scams. But there are still a number of reliable ones to chose from - unless of course if you're up against the NSA, in which case your best bet is to not use a computer or Internet at all.