So I have a chance to buy a used 2013 rMBP, 2.4 ghz, 512g SSD, 16g RAM for $1900 (no tax) Or New rMBP with Iris pro for $2000+tax Performance wise which one is better? I will for sure be gaming on it, just don't know much about this new intigrated Iris Pro card. I read up on it and I hear its slower than the 650m. I don't get it? Please help with which one I should buy and why.