Hello tjmim, I see that this is your first posting on this forum. Maybe you're not yet familiar with accessing reviews on the What Hi-Fi website. You might like to trace the evolution of the top Yamaha Aventage models by looking at the review of the model two years ago http://www.whathifi.com/review/yamaha-rx-a3010 . What Hi-Fi liked it very much. Then last year they reviewed one of the ones that you are considering http://www.whathifi.com/review/yamaha-rx-a3020 They liked it very much as well. And in this review http://www.whathifi.com/review/yamaha-rx-a3030 they also like very much the most recent model.
I doubt if there is a great improvement in sound quality of the 3030 over the 3020, because the 3020 was already so good. I expect the 3030 will have some more modern internet and other services, but unless you need those newer features I imagine (I've never heard any of these models, by the way) that you can save yourself a chunk of money by getting the 3020 now.
I'm hoping that one of the dealers, Rick at Musicraft or David at Frank Harvey, will be able to answer authoritatively.
As it happens, I have the step-down model, two years ago of the latest one that you are considering. I have the Yamaha RX-A2010 in my kitchen, and partly because I don't need the more modern internet features and upscaling to 4K and I don't play FLAC and other files (whatever they are) I have no need to change it, for the foreseeable future! I need it only as a surround-sound receiver, which it does to my complete satisfaction!