Poodles and Schnauzers are quite popular breeds. One of the reason is, that both come in three different sizes. The Poodle comes in toy, miniature and standard and Schnauzer also have three sizes, miniature, standard and giant and you can see the size comparsion on the screen right now.
Another similarity is their coat. While the Poodle is marked as a hypoallergenic breed that does not shed at all, the Schnauzer sheds a little bit more, but it is still a very low shedding breed. If you suffer from allergies, there is no such thing as completely hypoallergenic dog breed, since they all produce some dander or salive, but the Poodle has a high chance to not trigger the allergies.
Both breeds require quite a lot of grooming. Even though they do not shed much, they need often brushing and trimming. Many people choose services of professional groomer, because the grooming can be little bit too much time consuming.
Both breeds are very intelligent, constantly ranking among the smartest of all breeds. Its impossible to say, which one is smarter, but it is not that important, both are very intelligent. It is said, that the Poodle is easier to train, which is mostly due to the Schnauzer independent mind. The poodle also be friendlier towards strangers, while the Schnauzer is naturally good watchdog and can be trained to be excellent guarding dog. The Schnauzer is very loyal and affectionate to its family. Both, Poodles and Schnauzers, especially the smaller varieties bark quite a lot and they should be trained from the puppyhood to not bark excessively.
I would say, that the Poodle is better choice for novices or unexperienced owners, because the Schnauzers independent mind need a trainer who know what he is doing. But just like with all dogs, the key to succesfull training is a lot of patience, consistency and lot of treats and affection for good behaviour.
Another thing, especially if you are thinking about standard poodle or schnauzer, is their energy level. Those are very active and high energy dogs, that need daily proper outdoor exercise. It can be long walks, jogs or swims! These dogs will enjoy almost any activity with their people. You should also challenge them mentally, for example by some dog sport, daily training sessions or some interactive dog toys.
With enough exercise, these dogs will happily live indoors. Especially the smaller varieties are excellent for apartment living. Larger types are better for living in houses with yard, but even them will like to live indoors, next to their people.
Great fact about both dogs is, that they have quite a long lifespan, which is typically between 13-16 years. Smaller dogs typically live longer, so it should not be a surprise that smaller the miniature poodle and Schnauzer normally live little bit longer than Standard types.
Just like all dogs, even the Poodles and Schnauzers can suffer from some health issues. Some poodles suffer from epilepsy, progressive retinal atrophy or diabetes, while some Schnauzers can be prone to liver diesases, skin problems or von Willebrands disease.
There is also a cross between those two breeds, which is called Schnoodle. But just like all the crossbreeds, its impossible to predict its temperament and appearance, since it can inherit it from either of its parent.
If you are an active person who does not mind the extensive grooming needs, than both dogs have potential to be the best companion dogs. The main difference probably is, that the Schnauzer is more independent breed than the eager to please Poodle. It is impossible to say, which one is better, because it really depends on what do you expect from the dog!