The newer version has a much improved sparkling clean channel and more gain and dynamics on channel 2. Channel 3 is brighter with a good bit more gain on tap, 1 to 2:00 now would be the previous version maxed. Channel 4 is very similar to the older VH4. It's treble pot does seem to need to be opened much more than the older version, but gain and shred are ready at 11:00 on the dial.
I own a 2000 Vh4 and from then til now I've heard and played various heads. The sound differences on some models (if not all) might occur due to differences in tubes that Peter installs on each production line.