Sorry - I am in a non-US time zone for the next few days, hence the delay in responding.
You have already received perspective from a few seniors. These should help you with some data points for your decision. What I share may or may not have been shared already. Again, the idea is to provide as many data points for you to evaluate for your decision.
Re: Undergrad:
Syracuse will provide a big university with a diverse student body experience. Academically, you will find more challenges, rigor, and options at Syracuse.
Winters in Syracuse will be relatively colder than in NJ (a lot more if you are in south NJ) and could feel gloomy. Also, there is not much to do outside of the college environment.
On the other hand, Hofstra has a smaller cohort of students, and BS/MD students are known to be very supportive of each other. Outside of that, it offers opportunities for self-driven students. The environment in the undergrad school is more relaxed, and the college has a reputation for being a party school. It is also on Long Island and a short ride to Manhattan.
So, if you can handle the Syracuse winters (both cold and gloominess), Syracuse may offer a better undergrad experience.
Re: medical schools:
Both Upstate and Hofstra are solid medical schools. Upstate is an established school with years of churning out good doctors. They have been investing in new research facilities (some facilities look old) and offering good rotations within the university hospital and satellite facilities.
Hofstra has the advantage of being a newer and smaller school with the backing of the 23-hospital Northwell system. About 1 in 3 Hofstra graduates match into the Northwell system, including in competitive specialties. Hofstra definitely has the locational advantage of being on Long Island.
Re: Program:
Syracuse/Upstate has the advantage of having no MCAT and a GPA requirement of 3.5+. If you are up for doing a BS in Biology, you can choose a 3+4 option—something to think about.
On the other hand, Hofstra requires an MCAT of 80 percentile in one sitting. Its GPA requirement is 3.6+ (though easily achievable for BS/MD caliber students).
Subjective feel:
Where do you feel at home?
Which program do you have the most concerns about?
I hope this helps.