My #1 Rifle is an old M70 originally chambered in .300H&H and subsequently modified to .300 Weatherby. I absolutely love the rifle and the cartridge, but truth be told... there was never a reason to develop a .300 Magnum after the H&H. From a practical standpoint, none of the deviations is significantly better... and most of them can't fire a 200 or 220 grain bullet. By my reconing the only real justification for a magnum is the ability to fire a heavier bullet, so I'd say the H&H is still better than 90% of the .300 Magnums.
Get it. It is a classic round and just a lot of fun to shoot.