Hello, I have an older Macbook pro, upgrading to a 13" rMBP. Leaving everything standard, except I think I want to get the i7. I really like a snappy machine, don't like to wait, etc. and I feel I would get a noticeable boost with i7. However, battery life is also important. How much more battery power does the i7 take over the i5? Anyone have lived experience with i7, is it normal, or do you feel battery drains quicker?