
So far I've had 3.5 dobermanns :-P And I would not be without them. They are wonderful - charismatic, independant, loyal, cuddly, proper velcro dogs (avoid them if you don't like cuddling all the time!) but also very trainable, active and fun. A sense of humour is essential!
They are energetic, will walk for however long you want to walk for. Friendly, even my first rescue bitch with all her issues and aggression became the most loveable, soft dog and hugely popular among the other owners at the park! They will protect you as of course they are bred to do, but IME if properly socialised, will not do it unless it is actually necessary. In 11 years so far of dobes, I've only had one incident where my steady boy (my first dobe and first dog too) got in between me and something he thought was threatening, and at quite a distance - and that person turned tail and walked away quickly.
Bad points - health, first and foremost. As much as it saddens me to say it, dobes are not a very healthy breed. The biggest problem is dilated cardiomyopathy (DCM) - a few years ago the figure for dogs affected by it was 60%. I hope it is lower now but I'm not optimistic. If you go to a breeder, every dog in the breeding program and preferably the relatives too must be tested, at the very least by echocardiogram (ultrasound of the heart) and ideally by ECG as well, and ideally within
that, by 24 hour holter ECG. DCM is nasty - it doesn't show up in most dobes until they are at least 4 or 5, by which time they've been bred if they are going to be, and it can be there without symptoms for years before it hits (known as occult DCM - findable by testing but the dog looks and acts healthy). Testing should be done annually as well as it can develop very quickly.
Then you've got von Willebrand's, a form of haemophilia, are prone to hypothyroidism as well as a spinal condition called Wobbler's (forgive me, I'm not as 'up' on vWd and Wobbler's as I am on DCM!). Hips should be checked before breeding too. I believe there is also some prevalence of a particular eye disease, however I have not researched that at all. Hopefully someone else will know more about that and post.
Breeding is everything: as with any dogs, dobes bred from bad stock can have temperament problems. My first rescue was dangerously aggressive, primarily because she was completely unsocialised but I later found out that her mother was much the same which confirmed my suspicions that there was a genetic element interfering in my training efforts (she did become a fantastic dog but always had higher than normal stress levels). By contrast a well-bred dobe is just wonderful - soft, loving, friendly. My boy Linc is half dobe and he takes after them in that way, he's very lovable and huggable.
From the outside perspective they do have a reputation unfortunately - they used to be quite a bit sharper in temperament, and although breeders have put the work in to change that, the memories are still there, as well as from their time as a status dog. So be prepared for people crossing the road to avoid you, and be aware that if anything were to happen, the dobe would likely get the blame just because of what it is. Saying that though, not everywhere is the same - people round here are lovely and tend to adore them!
Physically they are low maintenance - decent food and maybe a once-over with a bristle brush or zoom groom every now and then, although I never groom mine at all. They do moult but not massively. They do need a fair bit of exercise and mental stimulation though, being intelligent dogs and independent to boot!
Boys are more cuddly and girls I find are more energetic and loopy at times but I couldn't pick one over the other. I've had one full boy and my half boy, and two girls, and I would take either again. I've done agility to some degree with all four and found no difference between the two except that the girls have been faster. All have loved clicker training, you can't beat the response and results you can get using positive training with these guys :-)
One issue that exists within the breed is a tendency towards same-sex aggression, particularly with the boys; I've had it with both mine, even with Linc only being half dobe. What I have found, though, is that it is primarily towards dogs of a similar size, and I've had no trouble with the girls at all. I think it's much less of a problem in the UK dobes as elsewhere. With a boston my concern would be more to do with clumsiness, they can be very clumsy dogs :-P But, I have a dog here every day for daycare who is a similar size to a boston, she's been coming here since just after I got that first rescue dobe and I've never had any problems.