I'm with you. I have my system to do data analysis. I have a late 2013 MacBook Pro and like it, especially the SSD and the Retina display. When I upgrade I want a faster processor, more RAM (I have 16GB now). I like my keyboard with the escape key. I like my ports (incuding HDMI). Like you, I want good battery life at a reasonable weight - and I don't want major surgery required to replace that battery if needed.

I don't want a walled garden of software. I don't mind a distinct authorization to run non-app store software (I break it, I own it...), but I want to run it easily. For example, I want an OS will easily let me install and run R and a current Python distribution like Anaconda.

While I want my phone, iPad, and MacBook to play nicely together, I want each to be optimized for a different set of tasks.