Oh, I like this topic! =p
It's hard to decide which one I like more....since both group has Yamapi. I think Yamapi was happier when he was in 4Tops, and that his relationship with 4Tops member is better than NewS member. Not that he's not getting along w/ NewS, just that he's even better with 4Tops. I remember Yamapi once said that ppl in NewS are members, his teammates, not friends. And if you look at the old video clips, you'd find that Yamapi seems to be happier around 4Tops, especially Toma. In 4Tops, Yamapi was more carefree and very dependent on Toma, but in NewS, it's the other way around that he's the leader who have to take care of the group members. But then I also want Yamapi to stay in NewS because I want to see him and Ryo-chan in the same team. So the perfect, ideal situation is for Yamapi to work in both teams just like Ryo-chan works for both NewS and K8. But it's not so possible........