The biggest mistake with these objects is over-using them. They are very helpful for internal memory management but they should definitely be avoided in APIs unless the point of the API is to do something like transfer ownership (e.g. factory method returning std::unique_ptr<T>).

Raw pointers continue to be fine in a wide variety of cases. Suppose the object model has something like a type T with APIs to access pointers to types A, B and C, the lifetimes of A, B and C are always tied logically to the lifetime of T and everything you do with the pointers to A, B and C is in the context of some T. This does not require special magic pointer objects to “share” A, B and C pointers because their safety is ensured transitively. So you might wrap T but you don’t need to wrap the others.

Besides, pointer objects are still annoying to use: sometimes they’re pointer-like (e.g. "if (somePtr)" works) and sometimes they’re not (requiring a ".get()"), and they seem to “infect” entire call chains. If you have previous API dependencies on boost::shared_ptr<>, you can’t easily replace those with std::shared_ptr<> either. Use them very judiciously, and always try the simplest thing that would work, first.