A hybrid dog or designer dog is not a breed, it is hybrid. Hybrid dog means, it is a mix of more than one purebred dog, bred over many generations to breed true for looks, and exhibiting the ancestral temperament and characteristics. Before these hybrid dogs were called mixed breeds

Difference between designer dog and mutt
Designer dog – purebred ancestry
Mutt – uncertain ancestry.

They’re looking cute! The offspring of a mating between two purebred dogs of different breeds is a mongrel, a mutt. Designer dog (media give this name to them) or hybrid dogs are quite popular now a days.

Breeding two different types of purebred dogs together can produce puppies with any combination of the various characteristics found in either breed. If a hybrid is of interest to you, don't leave anything to chance, that would not be fair to the puppy. Educate yourself as to the temperament, characteristics and care required for both breeds in the cross and be prepared for any combination of the two

Many breeders will breed multi-generation crosses. An experienced breeder can probably give a good assessment as to what characteristics to expect as the puppy grows. Dogs in the same litter can vary, and it is harder to tell what type of temperament the puppy will have since some characteristics are not evident until the puppy is past the usual adopting age.

In many cases, you will get a written standard and breeders must follow this written standard. Only dogs which make the written standard are to be bred. Purebred dogs are beneficial in that, when you buy a purebred dog then you will know what you are getting. You know basically what type of temperament and you know how big your puppy will grow and care the dog will need.  You know the capabilities of the dog like whether it is capable of agility, search, hunting and rescue, herding or just simply a loyal or companion dog.