I think it's internal dac is pretty good, and have compared with some £2k DACs.

You've got the choice with the SB, and that's a good thing.

Apparently when you lower the volume control on the SB the sound isn't quite as good (a friend reckons anyway), but not a problem if you use a pre-amp or have a volume control elsewhere.

I just use the SB's volume control, and damn any audiophile hoobywooby.