SATA3 is somewhat ubiquitous for all manufacturers as a selling point of their mainboards. Some manufacturers integrated the chipset onto the mainboard while some provides an external card to the mainboard.
In this video by ASRock, they compare the ASRock SATA3 card versus the Gigabyte integrated SATA3 on board. They used GPU-Z and found out that when the card is used, the PCIe full length slot is still running at PCIe 2.0 x16 while on the Gigabyte is at PCIe 2.0 x8.
The ASRock SATA3 card is also flexible as it can be used on your future motherboards and it also has eSATA3. This card is bundled with the ASRock P55 Deluxe mainboard (See Review : http://www.ocworkbench.com/2009/asrock/P55-Deluxe-Review/g3a.htm and SATA3 performance test with Seagate SATA3 HDD
Check out the video below