I have the Herron VTPH-2 and it is an excellent unit along with Keith providing great support. I have not heard the other units you mention. He usually offers a trial so you can listen to it in your system which is very important. I had a ARC reference (forget the exact model; $9600 list) on loan from the local ARC dealer and the Herron was very competitive with the ARC.
Good Luck
Chuck
Good Luck
Chuck