I think Ianto is adorable and Jack is 더 많이 a father like figure, thats what i like about him, not afraid to take charge, but he is very cheesy at times... I prefer Ianto 의해 only a little bit.
While Ianto is adorable and I 사랑 the Welsh accent. I'm goning to have to say Jack because of his cheekiness and style. BTW, His accent is hot as well! ;o)
