Maples are 24 karat gold, Eagles are 22 karat gold, Krugerrands are 22 karat also.

All contain 1 troy oz of actual gold. The Eagle has silver/ copper alloys, the Krugerrand has copper alloys to make them tougher and harder for actual handling.

Maples have higher purity but are softer and more prone to scratching when handled. 

Quick search turned this up from these sites.

http://www.goldbullionpro.com/canadian-maple-leaf-gold-bullion-vs-american-eagle-gold-bullion/

http://www.gemologistsam.net/krugerrand-american-gold-eagle-canadian-maple-leaf-and-the-australian-gold-nugget-an-introduction/