iFi iDAC, Micromega MyDAC, Shiit Bifrost?

My system currently consists of salk songtowers, parasound classic pre, NAD c270 power, an Epik legend sub. Analog is via a Clearaudio Concept w/ Concept MC through a Phonomena II phono pre. Digital is through an Oppo 83 standard.

I am very happy w/ analog. No complaints there. Though the oppo quite behind the analog setup it isn't bad per se. What I want to do is go the computer route w/ my Toshiba laptop connected into a DAC. I would like a dac that can best the oppo for when I want to play blu rays, sacds, and dvd-a's. Out of all the reviews I have read the iFi iDAC sounds like what I would most enjoy but it has only one USB input and is the most expensive (including the separate power supply). the others will allow me to also connect the oppo. The problem is that in all the reviews I have read and from what people on the forums are saying, the USB implementation on the MyDAC and Bifrost lags behind the SPDIF. So....

1. How do these DAC's stack up against the oppo?

2. Would I be better off getting an USB/SPDIF converter if I go the MyDAC or Bifrost route?

3. And probably most importantly, which of these would you guys go for?

Just to give you a hint to what I am looking for, I like warmth if I have to err on any side of neutral. The iFi's seem to be viewed most unanimously as being the most analog like of the group, but w/ the most limited of connections. The bifrost reviews all seem to be positive (after significant burn in) but the reasons seem to be all over the place, some say warm w/ a lot of bass, others disagree. The MyDAC reviews seem pretty consistent, it excels in airiness, imaging, naturalness, but lacks in the low end.

so what say you?
I own the MyDAC and wouldn't say it lacks in the low end at all. To my ear its low end is every bit as good as the Esoteric universal player it replaced, and better in most areas.

I can't speak to the others you mentioned as I've never heard either.

I am completely satisfied with my purchase and while I'm sure there are better DAC's on the market I have no real desire to upgrade.

Hope that helps a little...
I use both... USB from my audio server for critical listening as well as SPDIF from my DirecTV tuner.