hey, I am a serious deep ex user of the Dm800.
I had two units, one in fact is sleeping now in my bedroom - a shame.
The converters are pretty good, better sounding than ADATS, DA88s, PT3, PT4. It is 20 bits.
Love remembers ( George Benson) and Message in a Bottle (The Police remix) were done with this daw.
You might use the DA400, which is a converyer that transforms your dig coax outs into 4 analog balanced outs.
It also has the DIF 800, an interface that adds comunication and cascading options with adats, da88s, VTRs, digital boards and so.
For mastering I do not think I would use it nowadays.
Graphic interface is very videogame-styled and no on board or efx expansion.