The design of this is of very high quality, and it's an extremely clever concept - instead of tripping over your laptop power cable and damaging yourself, the cable or the laptop, the magnetic connection used on this adaptor means the cable will just pop out with no harm done. (NB this only works on newer mac laptops). However, design comes at a cost and this is not cheap - up to twice cost of another laptop manufacturer's adaptor, so make sure you don't loose it. It comes with an extension cable which lets you extend it to 2m, which is very useful, and it does run a little on the warm side. It's completely silent but makes a very quiet whistling sound when you remove it from a socket...