Hello! I am not going to give details about the situation (for obvious reasons) but here it is: I got accepted for PhD to a very good American university, in experimental particle physics and I met a famous professor here who is willing to be my mentor. I talked to some of his old students and they all said good things about him (both personality related and research related). The thing is that his students usually finish the PhD in about 3 years, while the average here is about 6. I am not sure if I should go for it or not. I really like the work that he is doing and a recommendation letter from him would definitely mean a lot and I am totally willing to put as much effort as necessary into the projects he gives me. I am just not sure if a 3 years PhD would be good for my future career? Will I get to learn enough? Will the post-doc or professor positions I will apply to might view such a short PhD as a bad thing (the students I talked to graduated quite recently so I am not sure about the long term impact of this)? Any advice would be greatly appreciated.