I myself am glad that we don't have to choose from one or two cartridges in the shooting world, how dull that would be.
I even like shooting wildcat cartridges where I have to size, trim, and fire form my own brass out of a different parent case. While they can be a pain in the rear they are fun to shoot and even more enjoyable when you take a animal with one knowing that very few others are shooting that round.
While the .300 and .375 H&H are quite capable for any animal on the face of the earth how about the other rounds that Holland and Holland came out with such as the .275 H&H mag, or even the .244 H&H mag along with a few others.
Now that .244 H&H would be a fun round to play around with.