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?
Depending on the country you're from, moving to Switzerland for a PhD might be an immediate improvement in your living standards, and that is certainly a good reason. It might also bring you on the spot to take advantage of the stronger hiring prospects in the industry, especially for engineers, mathematicians, biologists. But, from a strictly academic point of view, there are a few other things to consider.
It's true that there are world-class universities in Switzerland, some regularly appear at the top of international rankings. But there are also several mid-tier, "me too" institutions that surf on the popularity of the big ones.
If you ultimately plan for an academic career, the strength and international visibility of the group is likely to be more important than changing school/country. It's true that it's tacitly almost a must to have some sort of international stay in your CV but there are other less risky occasions for that than a PhD (e.g. a postdoc). A PhD is a big investment in efforts, time and money so go where the good science is.