Hi, I am having terrible time selecting among the three. I am CT state resident and the money is same in all the three schools (got grants etc to match) - Hence money is not an issue.
USNEWS ranks UCONN as 60, UMASS (Amherst) as 74 & Stony Brook as 96. However in terms of Graduate Math rating (2014) Stony Brook is ranked 25, UMASS is ranked 60 and UCONN is ranked 87.
I have no idea of dorm and food. Based on my research, the best to worst is UMASS, UCONN & SUNY Stony Brook.
Please note that I plan to do my MBA after BS (Math).
I think that they are close enough that you should ignore the ranking and consider other factors. Also be aware that rankings will vary from year to year. In general public universities have been sneaking up in rankings in recent years, probably due to more academically very strong students choosing to attend their in-state university (largely due to cost issues, I suspect).
Have you visited the schools? Do you have a feeling regarding where you would be more comfortable? Is there a large difference in cost? Have you looked at the courses available at each university, and is there a significant difference?