MacBook Pro eSATA Recommmendations
A clear winner emerged, offering huge value and superior functionality—
Note that some MacBook Pro models have electrical issues (Apple defect), and do not work reliabily with ExpressCards, see the MacBook Pro compatibility list on the OWC site.
Flush-fit, fast, driver-less, bootable winner
Inserted into the ExpressCard/34 slot, the OWC Slim ExpressCard is there when you need it, and offers considerably higher speed than possible with Firewire 800. It might as well be built-in, since it fits flush to the case.
Not only is the OWC Slim Express Card faster than the Sonnet Tempo Edge (which is almost twice the price), in most cases it offers 90% of the performance of the much more expensive (and bulkier) Sonnet Tempo Pro. Value doesn’t get any better than that.
Even more appealing, the OWC Slim ExpressCard is plug-and-play— no driver required, which helps prevent other troublesome issues that I’ve too often experienced with eSATA drivers. It was/is the only bootable card of the three.
With all of these cards, you’ll need an eSATA cable, which comes with most drives that support eSATA.
Beats the pants off Firewire 800
Performance with any of these cards is far better than with Firewire 800, something which should be kept in mind when purchasing a MacBook Pro, since only the 17" model has the ExpressCard/34 slot (certain prior generation 15" models also have the ExpressCard/34 slot).
Still, all of these cards are somewhat disappointing, because their best performance is only 45 - 70% of what can be had with the fastest peripherals on the Mac Pro. This is the fault of the MacBook Pro with its low bandwidth ExpressCard/34 slot.
Going faster and/or dual ports
If you’re looking for the absolute top performance, then the Sonnet Tempo SATA Pro card is a solid choice, because it offers higher performance and two ports. However, it does not fit flush with the MacBook Pro case and is not bootable.
The Tempo SATA Pro also requires driver software. As I’ve had more than a few problems with Sonnet’s driver software over the past few years, this is not appealing. For example, inserting the card incorrectly still can cause a kernel panic (crash). There is a certain amount of voodoo with all eSATA setups, but kernel panics are intolerable, and I’ve reported the problem more than once before to Sonnet, and yet it lingers.