Yeah, maybe I'm too harsh...but, it seems whenever Marshall and boost pedal comes up in a thread, Rackman seems to get his undies in a bunch and gets his best 'Ima mock the boosting dudes' face on.
I'm pretty sure he has no idea what a clean boost is, nor has he boosted an amp without the pedal gain on 10.
That's the only explanation that makes sense as to why he thinks a boost pedal makes the amp NOT sound like what it is anymore.