Is it important to do a PhD at a different institution than undergrad? I'm currently studying at a good school and I was admitted to do a PhD here. I got into some other good schools for my PhD, but for various reasons (e.g. less of a good research fit, weather, etc.) I feel that my current school would remain the best fit for me for grad school. I feel very, very happy here every day and I am very interested in the research taking place here.

My advisor is pushing me to go somewhere else as he says it will allow me to grow and do better research. Other professors have more of an indifferent view of my choice and said that I can't go wrong when choosing among the schools.

Do you think staying here would be a mistake? Would staying at the same school be viewed as a negative when applying for research positions?
He used a lot of hyperbole which has made the decision seem dramatic.


We do not know this person, but it is possible that this is the professor's way of saying he wants you to change your plan for a reason he does not want to tell you.  Perhaps he thinks the PhD supervisor you are considering at your own institution is not suitable, and he does not want that professor to realise he thinks they are unsuitable.  So he is telling you indirectly.  

Reflect on past advice this professor has given you.  Was it reliable?  Was it coded?  Ask more faculty for advice.  What do they tell you?  Ask your potential supervisors' former students what they think about the supervision they received.