Compared to other schools I visited during my college search, AU dorms are a big step up and this is coming from someone who has stayed in everything from a triple to off-campus housing to a single.
AU has two sides of dorms: Southside and northside. Southside is louder, houses more members of Greek life and generally consists of newer dorms.
Northside is quieter and has the honors floors. There is also Nebraska hall which is all apartment-style dorms, but is generally reserved for upperclassman.
The dorms are safe, warm and the bathrooms are kept clean. I of course cannot speak for all of the halls. I have heard complaints of lack of hot water in some dorms, or lack of shower pressure, but I've never experienced this personally.
I only lived in the residence halls for a year, but I had an overall decent experience. It truly depends on your RA and the people on your floor... From what I hear, things are changing for the better, nicer common areas with nice TVs, etc.
We want you to have the best college experience, so Plus-U moved in with Unigo. You're now part of the most extensive college network on the planet, with incredible resources to help you at every step of your journey.