Currently, I am in the process of selling my iPad Air 2 and my Mid-2014, upgraded 15" rMBP. I bought the 15" because of the screen resolution, and in the process, thought I might buy the upgraded model because I might "need" the dedicated GPU - I didn't. I regret the upgraded model because of the extra heat, reduced battery life, etc. It is a great machine, it is just a pain to carry around and I am not happy with the battery life and heat. I have to "pack it up" as opposed to grabbing and going (like the iPad). The iPad is great, except it doesn't do the extra 10% of things I need. Typing documents is a pain, and without a full filesystem, I cannot store more general file types. After playing with the rMB in the store, I am really pleased. It is beautiful, I love the keyboard, love the screen, and love the weight. I used to have a MBA before this pro and miss that machine the most - I see the rMB as a way to combine the best of the pro with the best of the air. That brings me to my point: do I go for the 1.1GHz/256GB model or the 1.2GHz/512GB model? All of my data fits into a bit less than 80GB, and that can probably be trimmed a bit too. Is the extra 9% performance increase worth the hit in battery life? Is it worth the $300? I am sure most of you have asked yourself this question and gone through this decision - which did you buy and why?