Jack Russell Terriers are NIGHTMARES!!! A Yorkie is 20 times easier to deal with lol. My first puppy was a JRT (BIG MISTAKE) and I loved that little girl like you would not believe! But I had no idea how to train a dog and she took over our household. She peed everywhere, chewed everything, jumped on the furniture, jumped on people, chewed on their pantlegs when walking... she barked wildly, attacked other dogs on walks, jerked the leash out of my hands while running after a squirrel or CAR... I kept her for a year, and then my mom made me give her to a woman who owned multiple terriers and lived on a farm in the country.
I was still living with my mom and going to college so I had to. It broke my heart and I still to this day miss India (my JRT). I wanted to get another Jack Russell because of her LOVELY personality, but decided on a Yorkie because they are still lively and energetic and intelligent... but less defiant.