Almost. A macho brace doubles the ev's you would receive, while any one of the power items adds for ev's to it's respective stat. For example, if you ko'd a raichu with a macho brace equipped, you would get 3*2= 6 ev's for the speed stat. But if you ko'd a raichu with a power anklet equipped, you would get 3+ 4= 7 ev's. Basically, the power items are better. Hope this helps!
