The Sony Handycam DCR-SX63 is the flash-memory-based version of the hard-drive-based DCR-SR68.
CNET did not review the Sony Handycam DCR-SX63, but we did review the DCR-SR68, which is very similar.
The main differences between the SX63 and SR68 are storage capacity and type. The SX63 stores video to 16GB of internal flash memory as well as Memory Stick Pro Duo and SD/SDHC/SDXC cards. The SR68 records to an 80GB hard drive, but can store to Memory Stick Pro Duo and SD/SDHC/SDXC cards, too.
The SR68 is slightly bigger and heavier than the SX63, but there are otherwise no differences between the two models. They have the same lens, processor, and image sensor, and as such should have the same video quality and shooting performance.