I would go for the Rottie. I LOVE Rotties, Pitts, and Dobby's! We brought Maggie home, knowing the Boo boo, would hate her. Boo boo has been the only dog in our household, for 12 years. Boo boo is a Shih Tzu/Mutt, and he is about 3 -4 times smaller than Maggie, but as long as he is the Alpha dog, all is fine. Just spend a lot of time with the dog you have now, when you get your new puppy, but make sure he knows that he isnt the baby anymore, and you arent going to give your undivided attention to him 24/7