Anandtech did a run down of all 4 capacities and 480/960GB drives perform extremely well. The 960GB for $600 is an unheard of deal on the price/GB curve for SSD's. Although $600 is still a huge price to pay for a storage drive, with this newer higher-density NAND we're getting another step closer to no longer requiring a small SSD for the OS and a big mechanical drive for data. One fast SSD can store everything now (for most users at least) and laptops will now have options for 480GB mSATA drives.
Higher-capacity NAND is also important for increasing the capacity of SD cards, USB drives, and other flash storage devices. 128GB MicroSDXC cards and smaller, higher-capacity flash drives are on the horizon. This is a huge step by Micron.