I own an iPhone, so I gave it a try. I didn't apply for any jobs, so I can't report on the status updates, but I can report on the search capability. First, it's very easy to use -- easier and less confusing than the USAJobs Web site. Search results appear almost instantly, and there are lots of them, though the total number is not reported. Searching on the word "editor" yielded 102 positions, mostly technical writing/editing positions including dozens at Navy field offices nationwide. Searching on "microbiologist" yielded 34 results, all from the Army, the Navy, or the Food and Drug Administration. Searching on "physicist" yielded 108 jobs -- again, many of them at U.S. Navy field offices. You can refine your search based on salary, grade, location, and 9 other criteria. And once a list of jobs is displayed, you can click on a button to display them on a map. A nifty feature.
The app seems pretty robust, though it did crash on me once. Users rate it 3 starts out of 5. Commonly reported flaws include crashing and problems signing in. (I didn't try signing in.)
If you're interested in government employment, this could be a useful tool.