The American type is a lighter dog, with a weaker bone-structure. The American standard says the following about the height at the withers: “dogs 26 (66 cms) to 28 inches (71.1 cms) ideal about 27 1/2 inches; bitches 24 (61cms) to 26 inches (66 cms), ideal about 25 1/2 inches… DISQUALIFICATIONS: Overshot more than 3/16 of an inch (0.5 cms).”
The European standard calls for the dogs of “Males: 68 to 72cms. Bitches: 63 to 68cms, with disqualification of 2 cm over or under the standard.” In fact most of the European champions would be disqualified because of their size in the American rings. At the same time blue and fawn Dobermans and the Dobermans with white patches on their chest or missing 1-3 teeth would not be allowed in European rings but they do qualify for American shows.

I am also not a great fan of the head type of the American Dobermans, for my taste it is too narrow with weak jaws. If you still have doubts, look at the best of what Europe has to offer at page. I promise you, you will want to have a European bred Doberman.

Another consideration is your future dog temperament. The Doberman was originally bred as a guardian and personal protector. As it was put by Ray Carlisle:
“The breed standard describes the desirable characteristic hallmarks of an ideal temperament. Namely it is PROUD, NOBLE, ENERGETIC, WATCHFUL, DETERMINED, ALERT, FEARLESS, LOYAL AND OBEDIENT. Descriptive words that should give anyone a pretty clear picture of how our Dobermans should look and behave at any given time. As judges we must appreciate and REWARD sound temperament when found and just as importantly RECOGNIZE and PENALIZE faulty temperament in our rings. A judge that overlooks shyness, fearfulness, unprovoked or inappropriate aggression, avoidance, or cowering in a Doberman fails not only in their responsibility to the breed, but the society we all live in. The more shy and fearful a dog is, the more likely to be easily stressed by things in its environment, and the more unpredictable and dangerous its behavior.
Correct temperament determines the ability of a Doberman to perform the function for which it was bred. If we expect to preserve and protect this breed as a functional entity in this modern world, it's important to understand and appreciate the purpose of that function. It is function that determines the purebred dog's most important characteristic—breed type. No function, no Type—no Type, no breed. “

The Dobermann was, indeed, bred to work. Europe still recognizes this. European bred dog will, in general, perform better than the American bred one in protection and tracking fields. This is due to the ZTP requirement for breeding in most European countries. America has bred down the working edge of the dog and it HAS become more of a pet/companion dog. They are still good watchdogs and will bark at strangers, etc., but they won’t make as good of Schutzhund or protection dog as their European counterpart. By the way a protection dog does not mean the dog that attacks. In fact a dog with unprovoked aggression is not good material for Schutzhund or IPO training and won’t be able to pass the ZTP requirement. A truly proper temperament will have the mind (intelligence) to be stable around children and non-threatening strangers, but will also be protective when danger arises.

On the other end of the spectrum is a dog that is skittish, shy and frightful. Unfortunately many American lines have produced the dogs with these undesirable characteristics.

Another consideration is health of the breed. The inbreeding of the Doberman and continuous use of a few popular sires paired with the hereditary problems of certain dogs resulted in an increased hereditary problems in North American Doberman population. Dr. Reinhard Haberzettl mentions 5 hereditary defects of the breed (DCM or cardio, Gastric Volvulus (bloat), Hypothyroidism, Von-Willebrand disease (vWD), Wobbler syndrome). He further mentions that the population of German and European dogs is currently similarly highly burdened with 2 hereditary problems (such as DCM - Dialated cardiomyopathy and Gastric Vovulus (bloat) )as a consequence of the same bad breeding practices.

The bottom line for me is that for pet or performance, go Euro.