I was playing my III+ yesterday and it sounded so incredibly rich. I was fiddling a bit with the settings, and I don't think I realized this before, but I have the presence set very high on it, something like 8 or 9 (it's in the back so I can't see it). This is a really big difference from when it was a regular III and I couldn't get the presence above 4 or so. This particular amp (a purple stripe) never seemed to be so crazy bright as the blue stripe I used to have, but it still took a little effort to stop it from being harsh. Not anymore. That's a big difference with the + mod.
Good God man!
Mine would slice my head off at that setting, and would still give me migranes if much above 6. I keep mine at around 5. If the high end needs further adjustment, I go to the graphic.
The magic number for me is 3, as in Master Volume. Once it's warmed up and crosses the 3 threshold, it enters God Mode on the lead channel.
There is a sudden boost of brightness and boldness, so I adjust my EQ settings for this volume, where I record and play.