There are two Aurora bikes: The Aurora and the Aurora Elite. From what I remember, the Aurora Elite has a really nice frame. The 520 and the Aurora have comparable frames, although the Aurora has a slightly inferior grade of steel relative to the 520. So the Aurora Elite is worth buying just to get the better steel frame. Both the Aurora and the Aurora Elite are geared similarly, and the Aurora Elite has nice components to go with that nicer frame.
I can't turn the big gears I could when I was younger, so the Aurora's are geared for someone with stronger legs than mine. Maybe this is not an issue for you, or maybe your dealer can swap things around. You might also see if you can get a deal on an Aurora Elite frame only and a build kit. The 520 has a little friendlier gearing. As I recall, the 520 has bar con shifters, and I don't remember what shifters the Elite has.
I will check my facts when I get home (and away from the web police), but the bottom line is that I would buy the Aurora Elite.