disadvantages of builder design pattern
A pattern is only disadvantageous when the pattern is been abused/misused. I.e. the pattern didn't solve/suit the actual technical/functional problem at all. You should then to look for another pattern to solve the particular problem.
This doesn't specifically apply to the builder pattern, but to design patterns in general.
Update: if you'd be interested to learn about the various design patters (specifically the ones mentioned in the GoF Design Patterns book) and the real world examples in Java API, then you may find this answer: Examples of GoF Design Patterns in Java's core libraries useful. It contains links to Wikipedia articles explaining the patterns in detail.
It does create more code (and could introduce more complexity) in the DTO than if you had for example contructor arguments and/or setters/getters.
In my opinion this is not a big deal, in most cases there is not a lot of extra code. The builder pattern will be more than worth it if you have an object that has some mandatory and some optional parameters.