That's our Rottweiler "Tush". This pic is when she was a puppy, she's now almost 2 years old.
Great dog, very active, very protective and very outgoing. They just need strict training, and need to learn their "role" in the household. They are pack dogs and need to learn where they stand. We got her at a puppy, but taught her very quickly that I was the leader of the house.
She learned that as the leader of the house that I get to eat first, I get to play with her toys whenever I want, and I walk through the door first, etc. As she got about 6 months old she loved to bite when playing, which had to be corrected.
We hired a trainer and brought her to the dog park 3-4 times a week to socialize with other dogs since she was a puppy which is very important to socialize with other dogs and people.
She learned that if she wants a treat she has to sit down. There is no jumping, no going on furniture. When someone comes into the house the first time she knows to sit down and wait to be greeted by them. When its time to eat she has to sit and wait for us to give her permission to eat and we can take her food away at any time and there is no growling. As long as you are consistent with the rules they learn fast.
She bit both myself and my wife when she was a puppy, but with proper corrections she learned that its not allowed. (we had to bite her back, and she learned very fast that when she bit us she would get bitten back.) She stopped biting within a week.
We crate trained her, and she continues to sleep in her cage every night. Very smart dog, she was potty trained within 3 days. And never had a poop accident in the house. Maybe 3-4 pee accidents during the first 6 months but after that no problem.
They are very curious and love to check things out. Garbage cans, toilet bowls, tissues, etc, they will get into mischief easily. If they see anything "run" animal, people, remote control toys their instinct is to chase after it. So its proper to always have them leashed outside.
But with proper training she has become a member of the family. Extremely protective of the house and our family. She let's us know when someone is at our house. Females are also on the smaller size, she's about 90lbs which makes her easier to control, as males can get up to 150lbs.
I was told that females are more gentle and more social. We also had her fixed when she was a puppy which they said would help with aggression. Overall I'd highly recommend a female as long as you have the time and dedication.
The most important thing to remember is no matter how socialized and trained they are, they are still animals, and still have natural instincts. But with the proper training they can be excellent pets.