I just ordered the Preon II with the warm tint, and a Preon 1 body tube.
I've picked up a couple of "neutral" tinted LEDs, I think they are Q3's and maybe a Q4: QuarK 123 w/the neutral white emitter; EZCR2 w w/the neutral white emitter; EX10 with a Q3 5A XR-E, Jet 1 Pro v 3 with a Q3; and an EagleTac P100C2 with, I think a Q4 flux neutral emitter. I find these colors much more pleasant and natural looking outdoors.
There is quite a bit of color difference between these "neutral" emitters, the EZ and the Quark being more yellow-ish, while the Jet and EagleTac are more on the "brown" - more like very light tan - side, and EX10 somewhere in between with a hint of orange.
It will be very interesting to see how the "warm" Preon compares to these "neutrals."