I might be the oddball here, having a M98 in 416 Rigby but calibers and rifles are like wine. The taste varies, some like white and red. One goes well with chicken, the other with red meat.
I have a 9,3x62 and 64 and don't need the 375HH. If I wouldn't be German I would have the 375 in my armory, a fine bullet! Besides you will get some bullets in the bush, this is not the case for the 9,3 outside of Namibia.
But back to your question, I would choose first what you want to do. For plinking in the states, then get a Winchester or Ruger in 375HH. If you want to go to Afrika at some point on a DG hunt, go with something stronger like a 416 Rigby or WM. They are great even for smaller DG cats like cheetah/leps or crocs and are ideal for everything bigger. The 458s will be too much.
Choosing the 416 calibres would reduce your choice to the Winchester or a CZ since Ruger only does 416 Ruger. The 416 Ruger is not so tapered and not ideal in warm conditions for reloading, besides it is pretty weak on the case load. I checked last year my Norma 416 Rigby PH monolithic solids in an Eli I shot (side brain and Security back headshot ) and the side one was close to exiting. The back brain shot passed through the brain and further. Ergo, it does the job. There you have a fine weapon for red meat.
For the PG I would go with a smaller 300WM.
As with wine, I like depending on the meal my white and reds. So, If you want versatility for PG and DG, I would go with the Sancerre of the PG, a 300WM and for the reds the Bordeaux under the big bores, a 416Rigby in a M98/ CRF.
