I've been thinking about getting something like this too. I came late to the PS2 party, and I currently have 1 memory card. I'm debating getting something to transfer files to/from a computer, or an extra card or two.
My question is this: do any of these work on Mac OS? I have experience with the PS1 dex drive, and with that you need to have a program on your PC; are the PS2 options like this, or do they work some other way? It sounds like at least one version runs on the PS2 and transfers to USB flash drive. Is that accurate?
Thanks!