I agree with BigKidz in that when you get into the
no-compromise components in either servers or transports the sound
quality is very close with each doing certain things better.
Please don't be offended by what I'm going to say: few people that make these comparisons are comparing apples to apples.
Some DACs have excellent S/PDIF inputs and poor USB inputs. Some DACs have excellent USB inputs and poor S/PDIF inputs. Few DACs have equal performance on all inputs.
The same is true of HDMI vs Ethernet vs USB inputs: not all are created equal so no one can make a blanket statement.
And what transport vs what music server are you comparing?
There's a huge difference between an Oppo multi-disk player and a high-end audio optimized CD transport. And there is a huge difference between one of the entry level CEC transports and their mid to upper level TL2N, TL1N, and TL0X.
The same is true in computer music servers: there is a huge difference between a MacBook Pro and an audiophile optimized music server.
When I hear people who consider a $1,000 Oppo multi-disk player an audiophile transport or a MacBook Pro a music server I just shake my head and roll my eyes. They may be excellent mid-fi bargains but no comparison to the potential of transports or music servers.
So I caution any of you who read threads like this who are inexperienced to take most of what you read with a grain of salt. Many of the people who post blanket statements in regards to the superiority of one technology over the another in reality have very limited experience.