I'd stay away from all Edirol products because none of them are bit accurate. The vx is a decent solution. I have one and it's good for DAT transfers in a controlled envrionment but in the field I'm always freaking out because the dongle (connection from the actual card to the breakout cable) is very weak. Also, the vx is limited to 24/48 although there are rumors of a new version that will do 24/96 (hopefully that won't be the only improvement).
As for other solutions...you might check out the emagic 2|6. Here's the website:
http://www.emagic.de/english/products/hardware/emi26.htmlI know of one guy who uses that as his interface and likes it. I know it does 24 bit as well but I'm not sure about sampling rates.
Finally, if your friend is looking to go for full out laptop taping he should check out the nuendo/rme multiset. It's the most expensive of the bunch but it looks like a great interface and I think it could be used for DAT transfers since it does have s/pdif I/O. Hope this helped some...
-d
p.s. Also might want to check out the metric halo Mobile I/O. It's probably to much considering it has preamps and a/d converters and it sounds like your buddy only needs a s/pdif interface. Just thought I'd give it an "honorable mention."