470NEDB,

Your question was a Searcy in:

470 NE,
500 NE, or
577 NE.

I faced the same question 4 years ago and selected the .500 NE because I thought the .577 was too heavy to comfortably carry on long stalks (8 miles or more).

In hindsight the .470 might have been a better choice because it kicks a little less, ammo is easier to find and resale is better.