When it comes to choosing one rifle over another, I too am torn most of the time, but recently my mind was made up when I shot a buddies CZ 550 Safari Mag in 458 Lott.
It just felt right, so I ordered one myself. I was going to build one on a Win model 70 classic stainless action I have here, but I decided I liked the CZ more for this cartridge, I also sold my old 602 in 416 Rigby and bought a new CZ 550 in 416 Rigby, the best part of these 2 new rifles is the new safety that is oriented the correct way, forward for fire!
I too have a Win Model 70 classic stainless in 375 Weatherby, it is tweaked and wears a HS Precision stock, can be 'switch barreled' to 416Rem Mag or any other belted mag if I bothered to buy a barrel. Although I have a 416 Rem barrel, I rarely ever use it, I just prefer the 416 Rigby. I can't put my finger on why, but I think it's more of a nostalgia issue than anything else.

Cheers.