Look I know the old axiom of garbage in/garbage out but I am now entirely convinced that the Steinberg Audio engine far surpasses the Protools system in terms of audio depth and warmth.
This is of course entirely subjective. I took a song that was tracked on Protools and exported it to Cubase SX 3.0 (No, I have not rushed to upgrade). I mixed it in Cubase and then mixed it in Protools using the same monitors, amps etc. I didn't use any plugins, mixed dry with only the built in EQs. The Cubase mix of the exact same tracks had a depth and warmth that made the Protools mix sounds cold, icy and brittle.