university presses
It utterly depends. A specialist or academic press can be both small and prestiguous.
My book (a Cajun-Creole music memoir) is just out, from a southern university press. I couldn't be happier. They have been a joy to work with, at every step of the way. Close editing, responsive, access to well known people in my field to be advance reviewers ("outside readers" as they call it in academic presses, to basically vet the book beforehand.) Savvy about marketing to "the trade" and not just academic markets. The physical production was beautiful too--that was the final surprise. Even my very seasoned NY agent commented on it.
Yes, I do have an agent. And naturally she did try the big publishers first. In another publishing climate, I might well have found a place on a trade publisher's midlist. But I'm very happy it ended up this way.
In one of those guidebooks about how to choose a publisher, I remember reading that you might be happiest at a university press if (along with care taken in the publishing process) you like the idea of an experience that will make you feel valued, that your work has some enduring value (vs. being a money maker.) And you'll know that your book will remain in print for quite a while.
University presses have good distribution, typically have local sales reps (mine has been a real advocate). They are nonprofits, of course, so they also have smaller print runs, smaller marketing budgets, and smaller advances. If making a killing is your goal, it's probably not a good choice!
But I'd say it's a very good option to consider, if your book lends itself to a university press. If you write nonfictdion with a regional focus, or a specialty area in which the press has an interest, you might fit. Also, some U presses do publish fiction.
My thoughts, anyway.
Good luck!