I'm glad you have had the same experience. Gary had a similar experience with the Source not having quite the soundstage of his amp (an Odyssey Cyclops) - and I don't doubt for a second that the soundstage is improved on other amps. What I will say, is that in comparison to the other Amp/DAC combos I have tried the soundstage is vastly improved.
I was skeptical about the Source, being that Dangerous focuses on mixing and studio equipment - but I have been extremely pleased. I have been considering upgrading to a separate amp, but I'm really just not sure if it would even be worth it. I know I would have to spend at least $1000 on an amp to get any improvementto hears, and possibly a great deal more.
Gary's DAC comparo is when I got a chance to hear the DS and I liked it a lot. I'm still thinking about getting one, so I can move around my house with a reasonably portable DAC/amp, and I periodically produce live events--it's a Swiss army knife of DAC/monitoring tools. I'd say $1000 is right as the buy-in before you start to hear significant improvements--and it means a large heavy amp with oversized transformers and capacitors.