I've read various opinions on this - but is there any kind of information or consensus? Has Apple changed anything in the air from a hardware perspective that consistantly makes the new air (and refurbished ones), better than the older ones. Is the fan better or does the machine run better. I understand that there have been no official hardware updates - but is that true? I'm trying to decide between buying a used mac air or a refurbished one from Apple. The used on is cheaper and from a trusted source - so the issue is more one of whether Apple has done anything to improve upon the build since the product was released.