I have a 15" MBP (2.2 ghz, 4 GB RAM) and have been waiting for the new notebooks to be released to decide about getting rid of it. I have found it to be quite heavy and difficult to use in crowded airline seats. I used my brother's MBA this summer and liked it a great deal, but am concerned about the problems that have been reported. Has anyone else "stepped down" to the new MB from the last generation MBP? I can imagine getting the MBA, but think the cost of the new model seems high for what one gets, especially in terms of disk speed (non-SSD) and RAM limits. Any suggestions for me?