Hi guys, Sorry for creating another thread about the same topic. I searched the forums, but I wanted to see if you all had advice that was specific to my needs. I'm currently a first year Mechanical Engineering and Computer Science double major. My 2010 MBP is serving me fine, but one of my family members needs it, and I know I'll need to upgrade eventually, so I'm hoping to get a new machine by next fall. I'm torn between the 13" and 15" rMBP. I'll upgrade both to 16gb RAM for sure, because I do run virtual machines from time to time. I will probably need to run CAD software eventually for ME, and I hope to dive into iOS development this summer. Obviously, it also needs to handle whatever else my CS classes throw at it over the next three years. Screen size is not a huge issue because I have an external monitor for desk use. Thank you for your help!!