I have seen a nice BR blue era layout about at the expos i help exhibit at, and it has DCC. I spent a happy half hour with 960012 at Ruislip watching a 37 trundle round with lights and sound. Unfortunately, the layout used 3-link couplers. So the whole image of reality (it was damn good mind) was lost by the fact the operator had trouble coupling the sound equipped 37 to the bogie bolster stock! This sort of negated the whole "reality" digi is supposed to impose. But the sound was great and I do believe he was using Lenz (thats what he said anyhoo).
the Digitrak stand at Warley last year had a gaugemaster rolling road with a Hornby loco on it. I thought it was ok, but the brake was just like "stop dead" and judging by the bits of motion the loco had ejected, people were not going easy on it! I'm contemplating getting Bachmann DCC for my LU layout, just so I don't have to wire sections.