While it's sometimes nice to be on the cutting edge, I'm generally more conservative when it comes to firearms and would select the H&H over the Ruger chambering any day of the week.
On the surface the .375 Ruger looks like the cat's meow. It wasn't until I tried to find ammunition for it that I realized that the .375 H&H was the better option for me at this point in time. Maybe in twenty years, if the round catches on, I'll opt for it. Heck, as it is I like the 9.3 x 62, and that can be hard to find ammo for at times, but not near as hard as the .375 Ruger.
.375 H&H is available worldwide. That says a lot right there.
Biker