"Would a McCormack preamp give me a completely different presentation?"
The answer to your question is yes, I am sure it would be very different. Probably better in some respects (definition, transparency, bass depth and control, etc.) but you would have to try them to see if they are a match for your system and taste. Don't worry about matching brands - just find a combo that suits your needs and taste.
All of the McCormack preamps are active designs except for the earlier "Line Drive" series of passive preamps. Several of them (ALD-1, TLC-1, Micro Line Drive) include passive outputs but have fully active sections as well.