I've been through a few. I won't count the 9.3mm's since they aren't considered full dangerous game rifles in all countries, even though I have a great fondness for my 9.3x62 and 9x74R rifles, and I think they are dangerous game capable.
First were a bunch of .375 H&H rifles.
Beginning with a Ruger RSM .375 H&H. Accurate, well made, looked good. But the bolt handle was far too small for the chubby stock, and was difficult to grasp or palm while reloading quickly. The trigger was very gritty and rough too. It was chubby and heavy. Sold it.
Next was a Beautiful Sako AV Safari .375 H&H. Handled superbly, balance was exquisite, style sublime. But accuracy was never what I was expecting. I tried various loads, re-crowned the barrel, epoxy and pillar bedded the stock, and tried a slew of factory ammo and reloads. 2" at 100 yds was about its best effort. It went down the road.
Then I tried a highly recommended CZ500 AHR custom full #3 upgrade. Beautiful rifle. Another .375 H&H. It never shot very accurately, didn't feed smoothly, scored the cartridge cases due to some some roughness in the feed rails, was too big and heavy, and it went away in a trade.
Then came a Sako M85 Laminated/stainless "Kodiak". Accurate, smooth, good handling. But the ejected cases sometimes hit the scope turret and fell back into the action. I got a skilled machinist to make me a new extractor with tighter tolerances and it became perfectly reliable. A new favourite. Then it sheared off the action screws - twice. I found out the recoil plate attached into the stock with two small wood screws had shifted, and needed to be epoxy bedded. I did that, fixed the cracked stock that resulted from the last sheared-off screw incident, and had no more trouble. I shoots accurately, operates smoothly, and balances very well in the hands. I like the secure 4 shot detachable magazine system and the wonderful open sights. Recoil is very manageable. A keeper.
Then I wondered about all the hype around historic Winchester M70 rifles. "Controlled round feed" and all that. Bought a current production M70 Alaskan. Forward balance with its long barrel, which I like. Crappy fold-down iron sights, a forgivable design flaw. Smooth operation, secure feeding and ejection, but only three cartridges in the magazine. But it would fail to fire one out of every three or four shots. Light primer strikes. I had a good factory authorized gunsmith check headspace, firing pin protrusion, and ammunition measurements. All were OK and within specs. It turns out that the Winchester factory in Portugal had installed a striker spring that was much too weak. I ordered a warranty replacement, and waited almost a full year for the new spring. The M70 now shoots reliably with the new spring, all primers are properly indented. But I've lost faith in the rifle. I'm trying to like it, but no joy. I'll give it another year, but I may just keep the Sako and call it my one and only .375
My only other dangerous game rifle is a Merkel 140 AE .450-400 3" Nitro Express double barrel rifle. I bought it used from a gentleman who wanted to hunt dangerous game but never actually went to Africa. It was supposedly regulated for Federal ammunition according to the factory test target. But Federal has never loaded .450-400 3" as far as I can determine. And it didn't shoot particularly well with Hornady DG ammunition. So I sent it off to JJ Perodeau in the USA , and at some considerable expense had it regulated for the commonly available Hornady ammunition. All good now! It is fitted with good Recknagel pivot mount and a Karl Kaps 1-4x scope. A great combination that improves its accuracy and reach.
It shoots accurately, operates reliably, and I think the .450-400 3" 400 grain bullet hits with more authority than the .375 H&H. I've used it for a couple of cape buffalo so far, and a moose and an elk closer to home. Oddly for a double rifle, all game was taken at ranges over 80 M. I'm thankful I have a scope attached. All game was killed quickly and with full satisfaction.
So If not considering my 9.3's I'd have to say my Sako M85 Kodiak .375H&H and my Merkel 140 AE .450-400 are my go-to dangerous game rifles, after trying a few. I have no desire to own any larger cartridges.
I have hunted with a rented .416 Remington Magnum, which I used to take elephant and plains game, I can see the charm and utility of that cartridge. It's just not for me at this stage in my hunting career.