My two cents: If you're happy with the Whitworth two position safety, blued steel & wood, then the Whitworths are definitely worth a look. Nice Mauser action and a little lighter than the Winchesters. The Winchester M70 has the 3 position safety but the Safari Expresses tend to be a little heavy in the barrel. If you're intent on the .458, the M70s might be less barrel heavy that if you went with the .375 or .416. If you insist on getting a .458 Lott, either the Whitworths or the M70s can be made into a Lott with little trouble (I believe).
I'd personally look for a stainless/synthetic M70 Classic in .375 H&H if I was hunting bears in AK. That's exactly what I used the last time I hunted Browns up there. The rifle is admittedly heavier than it needs to be with that large diameter barrel, but it shoots great and the stainless/synthetic is well worth it in Brown Bear country.
