I have a 2010 model MBA 13" base model CTO with 4GB ram, which cost me just over $1600 (after corporate discount) in March this year. When the 2011 model was announced I almost immediately wanted to upgrade, figuring the improved performance and keyboard backlight was exactly what I needed. Recently a friend at work purchased the base 13" model, so I had the opportunity to compare the two versions directly. We set them up identically and used them side by side for about a week in our shop to book and process jobs. The 2011 model had a noticeably (but not significantly) dimmer screen and required a slightly higher setting for optimal use. I understand there are different screens shipping with the Airs, but it was noticeable. Additionally, the 2010 model lasted consistently between 1 to 2 hours longer. This was a little surprising, based on the anandtech reviews I expected the 2010 to have an advantage but not at this level, especially considering mine has had significant use since March. It was even more surprising to find that over the week, the 2010 had been used roughly 10% more (in terms of jobs booked / time used). As a final kicker, and possibly something that was purely subjective, when connected to an external display with the lid closed the 2010 model recognised it quicker and was smoother in use. To be fair, this test probably didn't take much advantage of the 2011's strength, namely the faster processor. Only Chrome was running on each system, with between 6-10 windows open mainly with large complicated google docs spreadsheets. While the 2011 was appreciably faster, it really didn't have much practical advantage. Even in Eclipse, a rather heavy java based IDE, while it was faster it didn't feel upgrade-worthy. In the end, I managed only to make myself fall even further in love with my existing Air, and saved myself spending hundreds of dollars in the process. At least in the areas I care about (battery life) the 2011 seems to be a downgrade. If I was in the market for a new Macbook Air, I'd highly recommend a refurbished or second hand 2010 model with the 4GB upgrade, especially at the prices they're going for on eBay.