According to Guns.com the....
1) SA Operator is $62 cheaper, but less features,
2) SA Emissary is $7 more expensive, with less features & not as good looking as the Savage black non-railed 1911.
BUT, if you want a rail (not a must have feature in my book) then the Savage black railed version is...
3) $190 more than the railed Operator, but still with more desirable features in my book, and...
4) $120 more than the Emissary, but still with more desirable features and much better looking in my book.
My .02
This Sig 1911 has almost the same features as the Savage, but has milled internals, no MIM, plus lifetime warranty and was around $999.00 when I got it about 2 years ago, not a fan of a rail on a 1911, but I wanted a Sig 1911, so I gave in