The UI is clean, but gives easy access to needed features, and uses nice visual cues for navigation. Press takes advantage of the new Android UI language that Matias Duarte will always take a moment to talk about, meaning lots of swiping gestures, and sliding panels. Article views are formatted very nicely, much like you'd get with Instapaper or Pocket.
But, the app is still a work in progress and is missing some key features that have become standards of Google Reader apps. The number one missing feature is a way to quickly move to the next post when in article view, no arrows, no swipes. It's annoying, but the developer, TwentyFive Squares has promised that it is looking into it. The app also doesn't have a widget, or a dark theme, but it seems like the devs are working hard on the app, so these may not be issues for long.
Press does require a Google Reader account, and can't work as a standalone RSS reader. And, the app will cost you $1.99, but that means there will never be any ads. If nothing else, it's worth giving it your 15 minute refund window to test it out. If you want to try, Press is available in the Google Play Store.