Inexpensive USB DAC

I'm helping a friend with a system.

He has a Rogue Tempest integrated amp and Paradigm S20 v.4 speakers and will be using his computer hard drive as a server. NOT an audiophile, but needs a DAC to link up the computer to the amp.

I'm trying to decide among a Squeezebox 3, HRT Music Streamer+, or Musical Fidelity V-DAC, all the same price ($299).

He will be sitting at the computer when he plays music, so, though the SB3 will be more convenient, it's not absolutely necessary for functionality.

Which would give him the best sound?

Thanks for you help!
--Neil