I am using a 2014 MacBook Pro 15" (2.5 i7 w/ 16 GB ram) The most intensive things I run are Lightroom and a little Photoshop. I'm using 42MP Raw files. No real issues with the computer and I'm on the fence with keeping it or upgrading. The main things that appeal to me about the newer machines is honestly the size and weight. I believe the display is slightly improved. I would also like to move from my current 512gb storage up to 1TB. So my main question - would the 2018 13" Pro with the 2.7 i7 and 16 GB Ram be lateral to a slight improvement? Or should I just go big and get the i9 15"? I'm not sure if I benefit at all from the discrete graphics with the apps I run. I should mention that at my office I do drive a 4k display.