RMassoudi :
How do re-write cycles affect me? Is that in regard to longevity?
Yes,
In SSD's you have a lot of memory chips, (bundles of 256kb) that are laid out onto larger ships, and then onto the boards. Since you are changing the state of the little pieces, eventually they will wear out.
So, in regards to longevity, the pro's are better by about a factor of two.
If I remember correctly the pro was rated for atleast 500 rewrite cycle which is a lot more than SSD's used to be.
For a 120gb SSD, it would last for 60tb of rewritten data. At that point I figure that most modern SSD's will become technologically aged before they wear out.
However I would suggest the 840 pro, I have one in my laptop and I love it for the speed it boots in