Thanks for starting this thread! I just visited MSU, an got a sense that they have a broad and inventive scope of research, so it seems you'd be able to explore both your interests there. One thing I've just started looking for is how much support students get in terms of funding for conference travel, summers, etc. MSU is incredibly well-funded, with more conference/travel grants than anywhere else I'm looking. So, you could also consider the access to summer projects / grant-funded research / conferences in your areas of interest that would be afforded by MSU.
The big thing I'm considering right now re: comp/rhet programs is whether they are in a stand-alone writing dept or a subset of an English dept. I was accepted to four programs, 2 in stand-alone writing depts and 2 in English depts. Right now, I'm doing an MA in a large English dept, and while it's allowed for some cool interdisciplinary work, it has its limitations -- namely, that there are only a couple of comp/rhet courses offered every semester...