I wondered this too since I had a 2009 Hyroad and a 2013 Hyroad, which look and smell different from a 2014 and 2015 Hyroads I purchased. The '09 and '13 had the boysenberry smell that I was not a huge fan of (I made a post several months ago that the scent made me nauseous and I ended up not using the Hyroad because of it); the '14 and '15 Hyroad has a punchier berry smell which I can much better tolerate. Also, the '14 and '15 I can see much more shades of pearlized/lighter blue colors whereas the '09 and '13 Hyroads I had were dark blue and almost all black.
With all that said, I did not see a big difference in reaction since I had the '09, '13, and '15 Hyroads with the exact same layout.