I bought this SiiG card a while back and then returned it:SiiG eSATA Expresscard @ MicroCenter
I was very satisfied with the performance. I was using it with an Adaptec ACS-300 eSATA/USB 2.0 external drive enclosure with a fairly generic 120GB Samsung SATA drive.
Access times and transfer rates were exceptionally fast, three times faster than the USB 2.0 interface on the same drive enclosure, but not as fast as the internal SATA drive.
My problem with the device was related to the poor design of the e1705 and the connector portion of the card which extended outside of the lappy case.
The expresscard slot is located on the right side of the machine and the stiff eSATA cable when connected to the protruding connector of the card was a major kludge. I could hardly use a mouse to the right of the machine.
It's too bad that Dell did not include an eSATA connector or two on the rear of this machine, it would have been very useful. eSATA smokes USB 2.0 ...
In the end, I decided to just use the external drive enclosure with a USB 2.0 connection at least this way it does not interfere with the ergonomics of using the lappy.