diff --git a/packages/ember-metal/lib/set_properties.js b/packages/ember-metal/lib/set_properties.js
index 705385bab5a..3f3f7fafad2 100644
--- a/packages/ember-metal/lib/set_properties.js
+++ b/packages/ember-metal/lib/set_properties.js
@@ -20,11 +20,11 @@ import keys from "ember-metal/keys";
   @method setProperties
   @param obj
   @param {Object} properties
-  @return obj
+  @return properties
   @public
 */
 export default function setProperties(obj, properties) {
-  if (!properties || typeof properties !== "object") { return obj; }
+  if (!properties || typeof properties !== "object") { return properties; }
   changeProperties(function() {
     var props = keys(properties);
     var propertyName;
@@ -35,5 +35,5 @@ export default function setProperties(obj, properties) {
       set(obj, propertyName, properties[propertyName]);
     }
   });
-  return obj;
+  return properties;
 }
diff --git a/packages/ember-metal/tests/set_properties_test.js b/packages/ember-metal/tests/set_properties_test.js
index c397b9b8035..afc3091bf83 100644
--- a/packages/ember-metal/tests/set_properties_test.js
+++ b/packages/ember-metal/tests/set_properties_test.js
@@ -6,21 +6,19 @@ QUnit.test("supports setting multiple attributes at once", function() {
   deepEqual(setProperties(null, null), null, 'noop for null properties and null object');
   deepEqual(setProperties(undefined, undefined), undefined, 'noop for undefined properties and undefined object');
 
-  deepEqual(setProperties({}), {}, 'noop for no properties');
-  deepEqual(setProperties({}, undefined), {}, 'noop for undefined');
-  deepEqual(setProperties({}, null), {}, 'noop for null');
-  deepEqual(setProperties({}, NaN), {}, 'noop for NaN');
+  deepEqual(setProperties({}), undefined, 'noop for no properties');
+  deepEqual(setProperties({}, undefined), undefined, 'noop for undefined');
+  deepEqual(setProperties({}, null), null, 'noop for null');
+  deepEqual(setProperties({}, NaN), NaN, 'noop for NaN');
   deepEqual(setProperties({}, {}), {}, 'meh');
 
   deepEqual(setProperties({}, { foo: 1 }), { foo: 1 }, 'Set a single property');
 
   deepEqual(setProperties({}, { foo: 1, bar: 1 }), { foo: 1, bar: 1 }, 'Set multiple properties');
 
-  deepEqual(setProperties({ foo: 2, baz: 2 }, { foo: 1 }), { foo: 1, baz: 2 }, 'Set one of multiple properties');
+  deepEqual(setProperties({ foo: 2, baz: 2 }, { foo: 1 }), { foo: 1 }, 'Set one of multiple properties');
 
   deepEqual(setProperties({ foo: 2, baz: 2 }, { bar: 2 }), {
-    bar: 2,
-    foo: 2,
-    baz: 2
+    bar: 2
   }, 'Set an additional, previously unset property');
 });
diff --git a/packages/ember-runtime/lib/mixins/observable.js b/packages/ember-runtime/lib/mixins/observable.js
index b98c9801e8a..cfe63896170 100644
--- a/packages/ember-runtime/lib/mixins/observable.js
+++ b/packages/ember-runtime/lib/mixins/observable.js
@@ -214,8 +214,7 @@ export default Mixin.create({
     @public
   */
   set(keyName, value) {
-    set(this, keyName, value);
-    return this;
+    return set(this, keyName, value);
   },
 
 
@@ -461,8 +460,7 @@ export default Mixin.create({
   incrementProperty(keyName, increment) {
     if (isNone(increment)) { increment = 1; }
     Ember.assert("Must pass a numeric value to incrementProperty", (!isNaN(parseFloat(increment)) && isFinite(increment)));
-    set(this, keyName, (parseFloat(get(this, keyName)) || 0) + increment);
-    return get(this, keyName);
+    return set(this, keyName, (parseFloat(get(this, keyName)) || 0) + increment);
   },
 
   /**
@@ -482,8 +480,7 @@ export default Mixin.create({
   decrementProperty(keyName, decrement) {
     if (isNone(decrement)) { decrement = 1; }
     Ember.assert("Must pass a numeric value to decrementProperty", (!isNaN(parseFloat(decrement)) && isFinite(decrement)));
-    set(this, keyName, (get(this, keyName) || 0) - decrement);
-    return get(this, keyName);
+    return set(this, keyName, (get(this, keyName) || 0) - decrement);
   },
 
   /**
@@ -500,8 +497,7 @@ export default Mixin.create({
     @public
   */
   toggleProperty(keyName) {
-    set(this, keyName, !get(this, keyName));
-    return get(this, keyName);
+    return set(this, keyName, !get(this, keyName));
   },
 
   /**
diff --git a/packages/ember-runtime/tests/legacy_1x/mixins/observable/observable_test.js b/packages/ember-runtime/tests/legacy_1x/mixins/observable/observable_test.js
index 26ba600a88a..0c4095f2b62 100644
--- a/packages/ember-runtime/tests/legacy_1x/mixins/observable/observable_test.js
+++ b/packages/ember-runtime/tests/legacy_1x/mixins/observable/observable_test.js
@@ -274,41 +274,41 @@ QUnit.module("object.set()", {
 
 });
 
-QUnit.test("should change normal properties and return this", function() {
+QUnit.test("should change normal properties and return the value", function() {
   var ret = object.set("normal", "changed");
   equal(object.normal, "changed");
-  equal(ret, object);
+  equal(ret, "changed");
 });
 
-QUnit.test("should call computed properties passing value and return this", function() {
+QUnit.test("should call computed properties passing value and return the value", function() {
   var ret = object.set("computed", "changed");
   equal(object._computed, "changed");
-  equal(ret, object);
+  equal(ret, "changed");
 });
 
 QUnit.test("should change normal properties when passing undefined", function() {
   var ret = object.set('normal', undefined);
   equal(object.normal, undefined);
-  equal(ret, object);
+  equal(ret, undefined);
 });
 
-QUnit.test("should replace the function for a non-computed property and return this", function() {
+QUnit.test("should replace the function for a non-computed property and return the value", function() {
   var ret = object.set("method", "changed");
   equal(object._method, "method"); // make sure this was NOT run
   ok(typeof object.method !== 'function');
-  equal(ret, object);
+  equal(ret, "changed");
 });
 
 QUnit.test("should replace prover when property value is null", function() {
   var ret = object.set("nullProperty", "changed");
   equal(object.nullProperty, "changed");
-  equal(ret, object);
+  equal(ret, "changed");
 });
 
 QUnit.test("should call unknownProperty with value when property is undefined", function() {
   var ret = object.set("unknown", "changed");
   equal(object._unknown, "changed");
-  equal(ret, object);
+  equal(ret, "changed");
 });
 
 // ..........................................................
@@ -453,11 +453,11 @@ QUnit.test("setting values should call function return value", function() {
 
   forEach(keys, function(key) {
 
-    equal(object.set(key, values[0]), object, fmt('Try #1: object.set(%@, %@) should run function', [key, values[0]]));
+    equal(object.set(key, values[0]), values[0], fmt('Try #1: object.set(%@, %@) should run function', [key, values[0]]));
 
-    equal(object.set(key, values[1]), object, fmt('Try #2: object.set(%@, %@) should run function', [key, values[1]]));
+    equal(object.set(key, values[1]), values[1], fmt('Try #2: object.set(%@, %@) should run function', [key, values[1]]));
 
-    equal(object.set(key, values[1]), object, fmt('Try #3: object.set(%@, %@) should not run function since it is setting same value as before', [key, values[1]]));
+    equal(object.set(key, values[1]), values[1], fmt('Try #3: object.set(%@, %@) should not run function since it is setting same value as before', [key, values[1]]));
 
   });