Good afternoon, I've been looking for an upgrade for my 2011 MBA 13 (1.7GHZ/4GB/128GB) to remove the USB 2.0 bottleneck for external storage (considered Thunderbolt, but it's cheaper to just buy a newer machine). Originally I was just considering 2012 MBP 13 (non-retina), but looking at pricing on eBay, I saw a number of 2012 rMBP 13s going for about the same amount ($850 or so). I was wondering what the explanation was, considering that the rMBP design is the same age and sold for $500 more when it came out ($1700 vs. $1200)? Aside from upgradability, are there any real disadvantages to the rMBP over the plain MBP 13? Thanks.