I went into the Apple Store this afternoon and checked out the weight and the form factor of both the new 13" rMBP and the 15" rMBP. The form factors of both are great - whilst 15" is slightly heavier I'd have no prob taking either one around with me on a regular basis. The most demanding task I'd be wanting to use it for would be iMovie - I have a few TB's of 1080p go-pro footage I want to go through and make movies out of and trying to figure out which machine to go for. A pet gripe I've had in the past with an old 13" mbp I used to have (I think 2011) is that it would struggle or lag in iMovie as I scrubbed through video files cropping out sections I wanted to put into the project. Also importing video into iMovie would take forever I'd generally leave it overnight. Can anyone comment on whether the current version of 13" mbp is going to handle it much better or is this performance something that I'm going to see better overcome by the quad core in a 15" mbp? Also is dGPU something I'm going to need for this kind of work load or is this new iris pro fine?