Musical Fidelity V-DAC vs. Spitfire/Supplier Duo

I'm looking to try and upgrade Redbook listening using my Oppo BDP-83 as a transport. I'm on limited funds and am considering two options as of yet. Musical Fidelity's V-DAC or the Spitfire/Supplier Duo. I've read good reviews of the V-DAC, but I'm hesitant about the "wall wort" power supply. Specs on the Spitfire/Supplier Duo look promising and I like the beefier power supply option, just not sure about quality.
Am I placing too much of an emphasis on the power supply of the V-DAC? Or am I tossing dollars to the wind at this price point to try and improve the Oppo's stereo listening?
Thanks for any input and hopefully, personal experience with either of these DACs.