Hi, I have a 2015 rMB that has been totally awesome. Just got myself a 4k usb-c monitor, and it runs perfectly on 30hz no issues. With High Sierra the animations are super smooth as well (even when running both screens). I do some web-development, and this has been my main work horse for several years, but I'm starting to feel that things like Webpack etc. takes just a tad more time than I appreciate when developing. How much faster would an entry 2017 rMB be than a entry level 2015? I love that its fanless and portable, but the base MBP 13" is also compelling. In either cases, I would get 4k @ 60hz, right?