I have both, the Herret is a little faster. The Whisper is easier to reform and load.I do not think any suitable game would know the difference.
The Herret must be trimed and formed and then you can load. To me the Whisper has a little less recoil, but neither has a lot of objectionabl recoil.
I like and shoot both.
I LOVE to do the oddball cartridges that have to be reworked over from other cartridges.
Hence my selection of barrels include;
300 whisper, 30 & 357 Herret, 7-30 waters, 270 REN, 22ccm,445 supermag. 375 JDJ. And some others, but you get the idea.
Some you can now buy factory loads, but I bought them before that was an option.
My opinion is , do you like the idea of reforming the brass or not, if you do go w/ Herret, if
not go w/whisper. At the range or in the field both go boom.
Neal