diff --git a/lib/set.js b/lib/set.js
index 4a9dabf..d72159d 100644
--- a/lib/set.js
+++ b/lib/set.js
@@ -42,7 +42,7 @@ Set.prototype.diff = function(other) {
   var d = []
     , x
     ;
-  for (x in this.members) if (!(x in other.members)) d.push(x);
+  for (x in this.members) if (!(x in other.members)) d.push(this.members[x]);
   return new Set(d);
 };
 
@@ -58,9 +58,14 @@ Set.prototype.remove = function(item) {
 };
 
 Set.prototype.toArray = function() {
-  return Object.keys(this.members);
+  var ms = this.members;
+  return ownProps(this.members).map(function(k) { return ms[k]; });
 };
 
 Set.prototype.union = function(other) {
-  return new Set(ownProps(this.members).concat(ownProps(other.members)));
+  var ms = this.members;
+    , u = ownProps(this.members).map(function(k) { return ms[k]; });
+  ms = other.members;
+  u = u.concat(ownProps(ms).map(function(k) { return ms[k]; }));
+  return new Set(u);
 };