Hi all, I'm on a 2011 MacBook Air with a dual-core processor, thinking about an upgrade. The machine still works, but like a car that can't go above 25 mph - too many apps and/or browser tabs at once and it isn't usable. The configuration I go with will have 16 GB RAM and a decent-sized SSD, I've gone through all the other differences between the two models, so I'm really looking for opinions on whether the quad-core i5 or i7 in the MBP is worth the money over the chip in the Air. I don't do anything like video editing - just Word, a couple of other writing apps, Dropbox and Google Drive in the background, the Kindle app, FaceTime, Messages, , Adobe Acrobat, iTunes (with a large library) and Safari, with a bad habit of accumulating dozens of browser tabs at a time. It looks like the primary benefit of the Air processors is efficiency - an extra hour or two of battery life. But am I likely to notice a significant performance difference between the Air and the 2.3 or 2.7 GhZ Pro models, with the programs I'm using, either today or four years from now when software is incrementally more resource-intensive?