I picked one of these up last Friday along with a couple other DACs and feel like I've spent enough time with them to offer an some thoughts. I ended up comparing this player and a couple DACs over the last few days. I had this player and borrowed the TEAC DAC and a Wyred4Sound W4S DAC1. I also threw the Peachtree DAC-IT into the mix.
The Oppo is the best sounding source and/or DAC I've ever owned, period. Out of the box it was great, if maybe a tad harsh on the top end. Any harshness is long since gone now, the sound is very smooth and detailed with a great soundstage and air around the instruments. By comparison, the 83 that it replaced sounded a little congested and thin.
I"m not going to do a full comparison with the other DACs here, but will offer a summary. I found that the Oppo and W4S1 sound very similar, enough such that I can barely hear a difference between the two playing the same material. I don't know much about the W4S2 so can't comment how it would compare, but the Oppo and DAC1 sound very similar. If I had more time (The W4S is already now gone and I only had a day to play with those together) I'd probably be able to dig and find some differences, but in my given time didn't really hear any. Compared to the Peachtree DAC-IT the Oppo is more neutral sounding. The Peachtree still sounds great, but compared to the Oppo there's more air and resolution, like a very slight veil has been lifted from the sound. In comparison to all of the above the Teac sounded kinda lifeless to me, probably very accurate but sounds sorta flat.
So the comparison really is to the W4S and if all I needed was a DAC then the W4S would probably be good enough and would be my choice since it's cheaper. But given the extra functionality in the Oppo, if you want that extra stuff then it's a no brainer. The fact that it plays BluRays, SACDs, is a great CD player, is a great upscaler for DVDs and for video from other devices using the HDMI inputs, has inputs including USB to act as a standalone DAC, and finally as I discovered this morning is also a network player.
I got it set up this morning so that it streams music directly from JRiver, using the JRemote app on the iPad. So now I have the same functionality and convenience that I had before with the Squeezebox and then the Airport, but with a direct link into the Oppo and with yet another component removed from the mix. I confirmed with Oppo that music streamed over the network goes through the same DAC and gets handled in the same way as something via the other inputs, and my ears are telling me the same thing.
This thing is awesome, to have all this functionality and sound this good in a single box is unreal. In case you can't tell, I like it.