http://www.tomshardware.com/reviews/sam ... ,3578.html
Good read about SSD development and direction of development.
Good info on SSD internal operation.
Found this very eye opening, from what you read, about longevity of SSD's.
We have done tests using typical PC workloads (PCMark) to simulate 40GB's of writes per day on a 256GB 3-bit MLC SSD and have shown it to reach the specified limits of the NAND in 13.5 years; This is a long time in the life of technology. Hard drives were roughly 20GB thirteen years ago. Furthermore, some reviewers have shown that the 3-bit SSDs they have tested can handle much more writes than this. If you move to 2-bit MLC, you can bump this up to over 47 years. The question is: do you really need more than 13 years of writing 40GB's per day? If the answer is yes, then perhaps 2-bit MLC is for you. But, in reality, most people do not write 40GB's every day to their drive and do that for 13 years. And, it is likely the user would have already replaced their entire computer within that 13 years.