It's relatively cheap to try both - and I would recommend doing so. That said, I've AB'ed both my mini and my AppleTV with my Benchmark DAC and while both USB and toslink both sounded fine, the sound seemed somewhat better with the toslink. As for the cost of the cables - no doubt USB is cheaper, but you can get -excellent- cables for < $40 (a lot less in some cases) that will do your system justice. I've been quite pleased with the cables I've picked up from Bluejean - great materials, solid build, sane cost.