JRTs themselves are very smart and energetic dogs. They are pretty hyper, and we kinda gave up on training them (though they do know what we expect of them and when we are happy/mad towards them), though if you have enough patience, it is doable.
If you live in an apartment or do not have a large yard, I would not suggest them. Sometimes, if they do not have anything to do or anywhere to let out there energy, they will let it out onto your furniture. Trust me, my two dogs did it too our furniture...
On the whole, I love both of my JRTs and would never give them up for the world. Could answer any questions that you have about them, if you do...