The Corsair uses a controller from Sandforce, the 2200, while Samsung uses their own controller. The Sandforce controllers are infamous for not being able to handle incompressible data at the rated speeds, meaning that if you are moving something like a video or audio file or some encrypted data, you won't get anywhere near the rated 510MB/s that Corsair says you can. You will only get those speeds if moving compressible data, such as text and html files.
The Samsung drive, on the other hand, does not require the data to be compressible or incompressible, meaning that you will get the rated speeds no matter what you are moving around.
Also, SSD's write data in blocks of 4KB, so the 4KB random read/write number tends to be a better tell day to day performance than the sequential read/write numbers. In reality, on a day to day basis all SSD's perform relatively similarly to each other, so get the Corsair, since it's cheaper :P.