I love the DAC in the Oppo! But I would prefer a stand-alone DAC because:
1. I have no use for an optical player. All of my music and video's (including Blu-Rays) are ripped to a computer (which I call my media center).
2. Have to use HDMI input - but I much prefer USB.
3. Oppo 105 can't play native DSD through HDMI or USB.
The Oppo is technically a Blu-Ray player with a very good DAC. The digital inputs make it multi-capable. The Exasound DAC is only a DAC (small and slim). It has an asynchronous USB input capable of playing multichannel files as well as DSD. It's kinda like a D100 & D150, except it's capable of multi-channel files and has multi-channel analog outputs.
And how do most people use the McIntosh D100 & D150??? I'm thinking most people have it connected to a computer or media server.
At the last Newport Beach high-end audio show, many manufacturers (including McIntosh if I recall correctly) were using a computer as their source. The business of high-resolution downloads is also rapidly growing (e.g. HDTracks.com). Also, the number of companies making 2-channel DACs is growing very fast.
The convenience of having all of my music and videos on a computer is fantastic!