It has nothing to do with the city. It's the flagship university. Like Cal, Michigan, Bama, all of them just go by the state name.
Anywho, Nevada and UofU are fairly comparable if you're looking from a lifestyle point of view. The mormon thing is going to be as obvious as you make it. If you don't pay attention and hang out with people who drink and smoke, you won't tell. If you make every conversation about religion, it's all you'll focus on.
Reno gets a bad rep because 90 percent of people who say that shit have only experienced two days of Reno and they were downtown. It's a great place to be, really fun dorm life, and tons of cheap housing within riding distance of campus. Even downtown can be a blast if you know where to go.
In terms of Academics, you need to look at field of study. Nevada has it's shit ass aspects that drag them down, but there are also some really excellent programs there. The exact same statement can be applied to UofU.
In the end, you really can't go wrong with either, as long as you go in with the right attitude.