My old laptop, a 2011 air died and I'm looking for a cheap upgrade? I'll need a laptop for basic word processing, excel macros, powerpoint, Matlab and Stata. While on the surface, these requirements might necessitate a MacBook Pro, posts here say that Mb is severely underestimated. I can either spend 1400 to get a MacBook Pro or 550-600 dollars on a 2015 mb. A 2016 MacBook costs a premium of 200 dollars over the 2015 and offers minimal improvement. As a result, would appreciate it if you cold answer some questions. 1). Has your mb 2015 started experiencing lag with each iterative os upgrade? I.e. Do you see the beachball more often? 2). Has battery life detoriated? Do you still get close to the original 9 hours? 3). Finally, has anyone experienced running Stata and other technically demanding programs? I understand that processing times will be slow. I'm fine with slower results as long as there is no lag. Thanks so much!