If you're willing to shoot 250-500+yds, IMO, a rangefinder is a MUST HAVE item! Nobody, nobody can tell 375 from 450 yds in every situation but your bullet drop would be significantly different, enough to miss, cripple or wound an animal.
My first, only, and still present RF is a Nikon 800. I find it lacking on very few occasions and the only problem being having to twice change the batteries. I would upgrade to the Leica if i had the extra dough, but i don't. I'm grateful and happy with the product that i have.
Joey