I have had an 11-inch MacBook Air and a 27-inch iMac for a while which worked reasonably well but I kept ending up with files in different places from where I was. The reviews from friends and in the media of the 15-inch Retina MacBook Pro have been so good that I decided it was time to get one and move to a single machine. The MBA is highly portable (fits pretty much anywhere) but can be limited when it comes to development (Xcode and Eclipse). I've had the MBP for a few days and I have to say it is amazing. It is very powerful (can run multiple VMs) and the Retina display is visibly different (I'm guessing everything else is going to start looking pretty poor). One other difference that I've noticed is that the MBA would regularly have wifi slows (ping to my router would show timeouts every 5th packet and widely varying response times). The MBP has not had that issue so far. I was a little torn between getting the 13-inch MBP rather than the 15 to save on space but decided that the 15 made the most sense. I will likely post more on this later but right now I can't say enough about the 15 RMBP.