Deciding whether to study abroad or continue at my current university for my PhD, what factors to consider? I'm currently doing a master's degree near my home state and have been offered to continue at the same grad school with a PhD. The funding side of things has yet to be confirmed, but is almost secure. I also have another offer from a grad school in Switzerland for which the funding is definitely secured.


Regarding the position in Switzerland, (i) living abroad for a few years is an advantage and (ii) the research topic is more closely aligned to what I ultimately would like to focus. 
My current place has the advantage of (i) continuity and knowing the research group environment and (ii) research collaborations and publications that would probably exceed - in terms of both quantity and quality - that of the position in Switzerland.


What other considerations should I factor in to my decision and any advice as to which option I should choose?
One big advantage of changing schools is that you meet new people.  Most people have a few things they're really good at.  By meeting new people, you get to learn the new things that they are really good at.  More generally, you get to experience the culture of a different place and group of people (both academically and socially).  This helps to give you a more developed sense of what is normal (reasonable to expect), and likely will expose you to new insights.  All else being (close to) equal, I suggest that you move.