Greetings all, I'm in a dilemma here: I currently have a 13" Macbook Pro late 2013 model which is now over 3 years old. It works fine but I'm noticing that my SSD (512 GB) is full and it sometimes freezes over. I'm thinking of upgrading to 15" Mackbook Pro 2015 model. Cost is ~$3K for the way I'm speccing it. I'll keep the 13" model for travel purposes. Convince me if I should keep my 13" or give me the pros/cons on upgrading to 15". Much appreciated!