Hello, I have been using the MBP 17" for years. Currently, I am using the 2010 maxed out version (no SSD though) The 17" models have been serving me well but I am feeling exhausted carrying it around partly because of a change in work environment. I do not have a quiet office at school. I need to move from location to location on campus several times a day. The chance that the university will give me a quiet office is very low. I need a new machine at least as fast as my current MBP 17" 2010 which has a 2.66GHz i7 in it. At least 20-30% faster would be nice. I tried both MBA 13" and rMBP 15". The rMBP 15" is obviously lighter than the 17" I have. However, there is also a noticeable difference in weight between the rMBP 15" and the MBA 13". I prefer to use Mac OS but due to work, I have to use Autodesk Inventor, Solidworks, Borland C++ and another free C++ compiler sometimes. (Using Bootcamp, Inventor is running OK on my MBP 17" except in rendering. It is reasonable.) On the Mac side, I use Adobe Illustrator, Photoshop Extended and in the near future Premiere sometime (all from Master Collection CS6), all software from Office 2010, Keynote, etc. I also do 3D computer simulations. I asked the department to buy a powerful workstation but this has been on hold for over a month since they only allow 1 person to own 1 computer and that if they buy me an expensive workstation, somebody else will ask for the same thing. The university may buy a cluster of powerful workstations for people to share. There has been no decision even the discussion has been for weeks. I cannot carry my heavy 17" anymore. What suggestion do you have? If I were given a quiet office, I might go for the rMBP 15". However, as I need to move location several times a day, the MBA may be good. I do need a powerful laptop. It is hard to tell if the MBA is powerful enough to handle my needs. I have tried the rMBP running Windows under Fusion. It was like I were running Windows on a PC. As the food on campus taste very bad, I go to a local shopping center once daily to eat. The bus do not come regularly (sometimes I have to wait for 5-25 minutes). On average, it takes 15-30 minutes for the food to arrive. I have wasted a lot of time on this already. I certainly want to get some work done while waiting for the food. Any advice appreciated. Thanks. P.S With the Speck case and a computer bag that has nice protection, I carry 5.3kg across campus several times daily. If I carry an AC adapter and other items, it becomes heavier. A guy is interested in buying my MBP 17". However, he can only offer US$635. Isn't that way too low? I had both the keyboard and the case replaced 2.5 months ago. The machine is like a brand new one.