SPDIF internal sound card or usb converter

I would like some opinions on which has a better SPDIF out to a exteral dac.
A decent internal sound card with spdif out (Creative, Azuntech and such)or a usb to spdif converter.
I'm not sure which is better, but this is what I did.

First I installed a DEDICATED usb card for use only with a USB SPDIF converter. The reason I did this is that using the built in toslink out from my PC was not the best option in my set-up. It sounded thin and frail, if that makes sense.

To overcome this I bought a USB converter and it produced a few dropouts and clicks and pops. After some troubleshooting I was able to track it down to the usb port. That's where the USB card came into play. With it's own PCI channel and IRQ, the clicks and pops were gone along with the dropouts.

This computer is now sitting at work and I use it everyday. No problems using the USB card and USB converter.
I use the Toslink SPDIF output on my soundcard with excellent results. The run is over 20 feet. I use a HTO Striker soundcard @ 96K.
AESEBU is the best, followed by SPDIF, followed by USB, based on sonic quality. Have not compared Toslink so can not comment on it.