Yeah I looked into that one on there (great deal), I went and auditioned some integrated AMP's through my CM-5's at my local hifi shop and sadly the one where I felt a more noticeable difference was with the Arcam A-18,out of my budget for now. So I went ahead and took advantage of some Best Buy reward cash and got an Apple TV and then found an open box Arcam RLink so I just got that and ran those two through the optical (I sent the HDMI to my AVR) and then just to test out the DAC with the original cd in it I did a comparison using the Coax out from the CD player to the RLink vs. the built in DAC in the CD player (a 24/192 Delta/Sigma) and there was a noticeable diference specially in the Bass and a little bit more open soundstage. Also to see what diferences we could notice (i drug my brother that was in town and knows nothing of audio) I did the same file through the Apple TV-AVR set up (Denon 1712- Energy CB-10 L&R, CC-5 center and Take 5 satellites, ML dynamo 500 is shared between both HT and 2CH) this was a HUGE diference, I knew it would be different but not so noticeable compared to Apple TV - Arcam RLink - 2CH set up. Then just to see how it compared I played the same file through my Logitech Wireless Speaker Adapter for Bluetooth Audio Devices streamed through my phone (nexus 4 that has the same sample rate file in the computer via airplay) to the 2CH system, this was by far the biggest diference among the three DAC's (Built in CD player, RLink, and Logitech) and by far the worst.
I went through all set ups a few times and did sequencial comparisons among all 4 combinations and I noticed a couple things just from my empirical testing.
1) WAV and MP3 (328kbps) have a difference but very slight though the same DAC richer bass and more detail on the CD, for example we could hear someone else counting before the song began through CD and RLink that Ive never heard before.
2) DAC's do matter. I still believe there has to be a point of diminishing returns to where a $2k DAC wont be justified for me but $220 is well worth the improvement and ill invite anyone over to show them that a $40 DAC and a $250 one do sound different, or at least to my ears they do. And in this circumstance I much rather Airplay than burn MP3's and that alone is worth the money I spent as well.
I hope this made some sense and was hopefully helpful to someone