Phono preamp comparison: Herron vs. K&K

For those of you who listened to them side by side: how do you compare the sound of the Herron VTPH-1MC to the K&K Maxxed-out Standard and to the K&K Maxxed-out Premium ?

The sound of a phono preamp is very dependant, among other things, on the cartridge used, but anyway I am supposing you listened to them in good to very good situations. I use a Shelter 501 MKII.

By the way, they are both hard to find in the used market, but I have seen some Herrons, and not a single Maxxed. Can we conclude anything of that ?