Seems to be just fine with the 2 port version, just wondering if anyone had experience with the 4 port, as it seems possible to overdraw the power from a single sata power source if, say, 4 bus powered devices were connected.
I think it is possible. Maybe someone can double-check my numbers:
It is unknown how much is being provided by the PCI slot, if anything at all. To be safe I'll assume zero since the card doesn't work without the Molex power.
SATA power cable cable has three 5V pins that can each carry 1.5A each, which is 4.5A.
USB 3.0 is rated up to 1.5A@5V per port. With all four ports used, that is 6A.
4.5A is more than you need for things like flash drives, hubs, and hard drives with their own powered enclosures. I would be wary about how many bus-powered devices you attached and how much power they draw. For example, I wouldn't do anything crazy like using the port for charging four iPads at the same time!
In the other thread Tesselator pointed out the Orico cards don't have a dedicated controller for each port, so another drawback is that the more devices you hook up to the card and use at the same time, the lower your speed gets because they all share the same bandwidth. I have tested and confirmed this.
It is a very inexpensive and fast solution if you use one port at a time. It also uses native drivers which I like. But it's not a good solution if you want to hook up multiple drives in a RAID or some such thing.