I had a play with the new 13" and 15" MacBook Pro today with touch bar and am considering an upgrade. I currently have a 15" MacBook Pro Late-2013 with GeForce 750M. I'm thinking of going slimmer with the 13" version as when I'm editing in FCPX, or doing tasks that require a bit more screen room I usually connect to my 4k external monitor anyway. But then it occurred to me that the 13" doesn't have the discrete GPU, although I don't game at all on my MacBook or anything 3D oriented at all, so I'm wondering if there is any real benefit to having the discrete GPU for FCP editing over the Iris 550? Whats been your experience? The most I'll be doing is editing and compressing in 4K in FCPX, and of course playing back 4k video.