2.5" SSDs are now relatively cheap. You can get a 480 GB SSD for less than $100 and 960 GB SSD for less than $200. 16 GB DDR3L memory can be purchased for less than $50. The cMBP can easily accept any 2.5" SSD. The optical drive can even be swapped out for a hard drive or a second 2.5" SSD. The memory can be easily upgraded. Replacing the battery only requires removing a few screws and can be done in a few minutes. Oh, and did I mention having a 17-inch screen option for those that want one?