I am really frustrated. My first air had serious battery problems where it took over 10 hours to charge. I tried the battery condition etc and pram resets and it didn't help. I took it to the genius bar and they also noticed when you plug it in it says it says 10 hours to charge. They agreed there was a problem and replaced the unit. I got the second air home plugged it in and it was at about 80% After about 90 mins it charged fully. I took it off the ac power and used it until the batt ran completely down. I left it off and plugged it in about 11 pm. I woke up at 7am noticed the charge light was still amber and turned on the air and it was at 75% I am a network engineer and a desktop support technician before that, I have dealt with many PCs and macs and have never seen anything like this. I like this computer but just dont feel good if i have to replace it for a third one. I am going to give it through the weekend to see if the battery sorts out or if some sort of fix comes out but if not i am going to speak with a store manager and demand a full refund with no restock fee. i just got a macbook black last week and was going to return it but the air is so much more pleasent to use in the screen is awesome but the macbook has no problems.