I recently purchased through COSTCO and didn't catch the complaints about the highly frequent bluetooth signal breaks that makes it difficult to use without interupting your flow and train of thought.  Apple hasn't provided a fix other than a hardwire connection for the keyboard and mouse.  The wi-fi interuptions occur frequently; but not as routinely as the bluetooth signals.  I'd recommend a different purchase - I've returned to my MacBook Pro for production and us this only for web searching.  During this review, I lost signals twice!