Pros: Tons of inputs, easy source selection
Cons: Some interference between sources
All the other reviews sum up my feelings about this. It's a great all-in-one component. I have my PS3, computer, stereo, and portable devices all feeding audio to the TubeMagic D1. It handles them with ease and doesn't get uncomfortably hot like other amps I've used.
Only flaw I've noticed is that my computer generates a slight signal noise that carries through the SPDIF connection. It's unnoticeable when the volume is set to comfortable levels for the computer, but if I leave the computer on, switch the source to my PS3/portable device, I have to turn the volume up, and the signal noise becomes noticeable until I turn the computer off or disconnect the SPDIF cable. This could be solved by eliminating the signal noise from the computer, but it's odd to me that the noise isn't "turned off" when using a separate source.
edit: The signal noise was from a ground-loop, and I fixed it by using a CyberPower UPS that provided cleaner power.
That's just one possibility, but I imagine it's probably what it is.