Looking to upgrade my air this afternoon and been checking out the refurb section and found to possible contenders: £1099 - New 13.3-inch MacBook Pro 2.4GHz Dual-core Intel i5 with Retina Display (June 2013) 4gb ram and 128 GB or £1189 - Refurbished 15.4-inch MacBook Pro 2.3GHz Quad-core Intel i7 (June 2013) 8gb ram and 512gb. My partner has the first one and I currently use a mid 2011 air. I do quite like the retina 13" but I find everything is too large on the screen. I have never tried the 15" but like the idea, is it going to be much more powerful that the retina? Many thanks.