As a string player who is called upon to do overdubs, I have heard about (but never experienced) the Gordon pre. A friend (a fellow fiddler) was blown away by what he termed the "third dimensional depth" of the Gordon. Personally, I have noticed (but enjoyed) sessions using the Millennia because of what I experience as a nicely flat, 2-D gloss it lends to the sound. So, I'd really like to experience the Gordon.
In my experience, the informational feedback that certain mic/preamp chains gives this individual acoustic player when I hear the initial take's playback changes the approach I use when under the gun -- both consciously and unconsciously. If I am hearing a lot of detail, it leads me to go in a deep, focused direction. If there is something of a haze (even if flattering) it leads me into another (don't throw pearls before swine: just go for energy, not on subtle nuance or touch).
Which brings me to a question for you experts: any controlled A/B of the Gordon and Forssell smp-2?