There's always going to be examples of any breed that aren't going to fit with a new horse owner. I know of quarter horses I wouldn't let anyone but very experienced riders handle. The 2 haflingers I've personally ridden and worked with have been extremely sweet and willing horses.
At the end of the day, that's why its most important to pick a horse as an individual, regardless of breed! For the most part, I wouldn't recommend a thoroughbred to a new owner, but there are a lot of easy going, quiet thoroughbreds out there who are beginner safe!
So to the original poster, take your time and learn all about all kinds of horse breeds, and pick a couple you think overall would satisfy what you are looking for in a horse. Then be very, very particular in choosing a quiet, safe horse. And if you happen to find one that is of another breed than you intended, then go with it! Choose the horse, not the breed!