At present, I have the 2010 'Rev C' MBA, and have been very happy with it. I bought it in September 2010, and have Applecare on it. The specs, impressive for the time, are 2 GB RAM and the Apple 128 GB SSD. However, I usually consider changing a computer every two to two and a half years, certainly, in this case, before the Applecare runs out. At present, I am contemplating buying (later this year) the so-called 'ultimate' MBA, the one with 8GB RAM and 512 GB SSD. Does anyone have it and what are your thoughts on the machine? Is it significantly more powerful - and better - than the more obvious 4 RAM GB and 256 SSD? Apart from future-proofing, and (I assume) stunning performance, what are the other advantages to the 'ultimate' MBA? Having had the advantages of a computer with a SSD drive for more than the past two years, I certainly will not contemplate returning to the world of the HDD. Also, as I travel a lot, the portability of the MBA is a huge plus. In the long term, I would contemplate buying a rMBP as a desk computer, but only when Apple adds a large SSD drive to it at a price that will not require sale of one's private organs in order to finance such a purchase, and would, in addition, then also buy a powerful 11" MBA for travel. But that is for the future. For now, the best combination of power, speed and portability remains the 13" MBA and I am curious to know what those of you who have the 'ultimate' think of the machine. Meanwhile, I thank you in advance for any responses.