University Presses are very valuable, though some of them have come under the budgetary axe from their home Universities in recent years.  They typically produce much more durable books than popular presses (don't come at me with anecdotes of popular press books that are exceptions to this rule, because they are in fact exceptions, and terrifically rare ones).  Because they are not so desperately profit-driven, and because they typically have longer time-horizons than many other presses, their books typically endure longer.  (Again, typically.)  Also, because they emerge from a context of commitment to reality, more or less, they are typically much heavier in non-fiction than in fiction, though almost all "critical editions" of fiction come from university presses.

This article takes you to a nice list of 75 books from university presses that will help you understand the world better.  And they're not wrong.  Some excellent scholars are on this list, even in ethics and religion; I think especially of Fr. David Hollenbach, D. Stephen Long, Todd May.  There are so many good presses, producing solid books; and there are even a few really good books published by university presses every year, but hidden from general acclaim by being pitched to very small specialized audiences.

University presses are always under threat, and even moreso today.  If you're out there, and haven't bought a book from a university press this year, do so--the cosmos will thank you.