I was just talking to my Dog trainer/dog walker (majority of his work is training) not the advent of designer dogs, and the naievity that people who get them have about them.
1/ you are taking pot luck in terms of looks and temperament. Poodles and cockers both lovely dogs, but different. the breeders are not breeding for temperament and a look - they are breeding to meet a demand. A demand generally created by people who don't have huge experience in the dog world (I am sure I will get flamed about this), and get told "poo's make fantastic family dogs.....well most breeds make fantastic family dogs, its all in the socialisation and training. Which I will come to in a minute.
2/ Because these breeders are doing it to support a demand, and are not breeding to maintain a breed,(also primary motivation is to make money not a passion for the breed), they don't health test, so you can end up with a very poorly dog - which I might add you have paid a lot for.
3/ Because these are backyard breeders, who at one end of the scale - think I have a nice bitch and there friends have a nice dog - one of which is a poodle - it would be lovely for it to have pups, to the other end of the spectrum are cynical puppy farmer who use there animals as machines, they have no idea, or just don't bother to do the socialisation that is required. Actually socialisation is bit of a misnomer, its not only about meeting people and other dogs, its about experiences outside of a cage or house, so that the puppy grows into a a well adjusted dog who approaches the world around it with confidence.
My Dog trainer is in-indated with "poo's" at the moment who have training issues, down to poor "socialisation" as puppies, with with the so called "breeder", and then once they have come home. One because the breeder hasn't talked to families taking them about what is required to raise a healthy dog, and two because a scary number one them have developed health issues as they have gone to their new home (one parvovirus) so have missed key socialisation and experience in that window when it is key.
I am sure people will re-butt my arguments about KC breeders being dodgey and certainly within our breed their are some - but people within the breed no about them - so if you do your research within the breed you want you will find good breeders far more easily.
If you don't care about what your dog looks like and what sort of temperament - get a mongrel from a rescue, don't pay a fortune for one.