Here is the bottom line...
SATA speeds refer to maximum BURST rates in BITS (b) per second, NOT BYTES (B) per second. So, SATA2 runs at maximum BURST at 3 Gb/s, or about 300 MB/s. SUSTAINED read and write, like what we do with images, is MUCH slower even on SATA2 drives.
My BEST SATA2 drives are capable of just over 100MB/s on SUSTAINED read or write tapering off to 70MB/s or so toward the slow end of the drive, so FW800 at 80 MB/s is for all practical matters pretty darn close... SATA1 drives only ran at about 50 MB/s to begin with, so not even significantly faster than USB2 or FW400... Fortunately, SATA2 drives are twice as fast. BTW, this is why you need to remove the jumper on Seagate SATA2 drives, as they default to SATA1 speeds if the jumper is left on
The other problem with eSATA is it is NOT hot-swappable or hot-bootable. Hence, the only time I would say it makes a difference on an EXTERNAL drive, is on a desktop where it's permanently connected via eSATA, or for when you want to transfer more than a couple hundred GB and have limited time on a laptop. Otherwise it is not worth having to shut the computer off, connecting eSATA and rebooting to run it. By contrast, the convenience of plug&play FW800 is a breeze on a laptop or a desktop for transferring even a few hundred Gigs of images...
These are the reasons I didn't recommend the eSATA version portable drive box for your laptop: I didn't feel it was worth the cost difference to gain a function you probably would only rarely or never use with your laptop. However, I feel the opposite is true for a desktop: I have my desktop external drives connected by eSATA since I don't need to disconnect them and use them just like internals, so the lightening fast burst and faster sustained R/W is welcome.