Overall, how has your experience been? Has it been dramatically different? I'm coming up on two years of using my current 12.9", and it's been my favorite Apple product in recent memory. I'm thinking of upgrading to the newer version for the upgraded camera, gold color and some more storage (I currently have 128G; I would get 1256G). To those that have made a similar upgrade, has it made a big difference in day to day usage?