I have a friend who bought one when he found them on sale a few years ago.
It hurts! It kicks harder than my 458 Win Mag. It is a sharp kick!
It reminds me of the Weatherby calibers; i.e. the 338 Win Mag vs the 340 Weatherby (as well as other pairs). Weatherby used a proprietary (read expensive) cartridge, added an extra pound of powder and gained a couple hundred fps. And doubled the felt recoil!
I think the 375 that you heard about being the "gun of choice in Africa" is the 375 H&H Mag. Now there is an old workhorse - recoil is tolerable, affordable ammo can be found in about any store that sells ammo (in Alaska or Africa).
It has been the standard moose and big bear gun around here for many years.
Back to my friend - he had his 375 RUM ported and it is now bearable to shoot but he can't afford the ammo. And it seems to be getting harder to find and more expensive every day. He mentioned seeing it somewhere for $200 a box!
If you own a RUM (in any caliber), my advice is to lay in a cache of brass and a set of reloading dies.
But you are right about it being a killer, same bullet as the H&H, just a little faster.