Routing Audio within VC, TI Polar and PC

[synthfiend]

sorry if this ground has already been covered but I have only had my Virus a few weeks and am a bit of a newbe

I run Ableton on a PC with an M-Audio Audiophile 192 and a TI Polar.

Correct me if I am wrong but there seems roughly 3 ways to route audio when creating a track with Ableton and the Virus TI;

1. the Access way using virus control and the PCs sound card: where the virus streams digital audio out through its USB to Ableton on the PC. This audio is summed with any loops within Ableton and comes out of the audio outs on the PCs sound card.

2. the Access way using vc and the virus as a sound card: where the Ableton loops etc are streamed via digital audio through the USB to the virus. The virus must then summ its own audio with that coming from Ableton and it comes out the external audio outs on the virus.

3. using an external hardware mixer where the sound cards audio out and the virus's audio out are summed within the mixer (traditional way).

So far I have tried 1. and 2. and am trying to work out which sounds better, the D/A converters on the Audiophile 192 or those on the TI Polar.

Does anyone have any opinions on which of the 3 would give the best audio quality. I know some people are believers in hardware summing, but I am interested in anyones input.