Not sure what you are talking about on Consumer Reports rating differences? I just looked, and can't find anything significantly different in the ratings of both models.
I have a 2014, so can't speak to the 2015. From what I found in researching them when I was looking to purchase - they are essentially the same model. A few "fixes" on the '15, but nothing significant that I found.
+1 on the infotainment comments. It takes about a minute for everything to boot up, so if you are used to jumping in and going with the radio and all options working before you pull out of the driveway - then you may want to reset your expectations or look elsewhere. You may still have occasional blank screen or other issues, but it's pretty rare. And no, you typically can't run everything on your iPhone/Android device from the touch screens. It does have a lot of options buried in menus, the stereo isn't too bad, and overall I'd give it a B+.
Car is fun to drive, I think it handles pretty well (even with the run flats). Has plenty of power for regular driving, and moving around someone who is hogging a lane. I feel the seats are comfortable, the dash placement is good, and while the trunk is pretty small as compared to other "mid-size" cars, it is typical. The standard wheels will get road rash if you look at them wrong, but again I believe this is typical with today's wheels and tire offsets.
If you have a great deal on a '14, and you are okay with the above, then make sure all the updates have been done and pull the trigger. If you find a similar '15, with about the same price, then I'd say go for it. Pretty much what I'd suggest with any car purchase.
