I just made the same upgrade from a 2011 i7 MacBook Air to the 13" Retina MacBook Pro and I disagree with nearly every part of this review. Battery life seems on par with my Air. Performance is improved on the MacBook Pro. A good example is something like installing imagemagick from Homebrew. On the Air that resulted in max-fans, the MBP handled it without breaking a sweat. I haven't noticed any UI sluggishness. I loved my Air (like many have said, it's my favorite computer I've ever owned) but this machine is every bit as nice, feels more capable (CPU-wise) and has a gorgeous display. The only drawback is the extra weight and thickness.