The Wadia 27ix is, without question, the finest DAC I've heard. I've not heard the Bel Canto Dac3, but I suspect it's good...I've heard the DAC1 and DAC2. I suspect that there is a very large difference between the two, but "very large" is a relative term at that end of the market.
As a disclaimer, I have Wadia gear myself...though nothing so up-market as the 27ix. I like it a lot. I also know most of the folks over there pretty well (I work 10 minutes from their office). Having said all that, I am a fan of the Wadia house sound. They are also constructed like what one might expect of Armani tanks. Oh, and in a pinch, you can use your Wadia (with its digital volume control) as a more than passable balanced headphone amp.
My advice is to get the Wadia. You'll ultimately be glad that you did IMHO.