after talking to the founder of computeraudiophile.com, he helped give me that little nudge to go with the MacBook.
I was experiencing shifts in imaging that really bothered me. the vocals also didnt have much shape or texture, even less than the squeezebox I was replacing. I was also concerned about the optical output adding too much digital jitter to the signal. Another issue was my desire to have a smaller screen to navigate the menu's compared to the 57' screen i was currently using. I like to listen to music in the dark and the big screen displaying the album art took me away from that a bit.
these are just my opinions, but I have spent the last few years trying to find a cheaper way to have a music server. i finally sucked it up and decided to do it right. if you are on the fence, go ahead and get a MacBook and a USB DAC of converter to use your own DAC, you will not regret it.