Added ingenious change detection trick from @smoothify though at the cost of verbosity controls. (Quiet or verbosity > 1 breaks change detection. Also added better use of module_common methods.

library/files/synchronize

@@ -40,11 +40,6 @@ options:
     required: false
     choices: [ 'push', 'pull' ]
     default: 'push'
-  verbosity:
-    description:
-      - An integer controlling the amount of information returned during processing. See the C(-v, --verbose) option of the rsync man page for details. If verbosity is not defined or a value of 0 is assumed, the C(--quiet) option is passed and information is supressed.
-    required: false
-    default: 0
   delete:
     description:
       - Delete files that don't exist (after transfer, not before) in the C(src) path.
@@ -77,9 +72,6 @@ synchronize: >
 # Synchronize and delete files in dest on the remote host that are not found in src of localhost.
 synchronize: src=some/relative/path dest=/some/absolute/path delete=yes
 
-# Synchronize and return verbose information from the rsync transfer.
-synchronize: src=some/relative/path dest=/some/absolute/path verbosity=1
-
 # Synchronize using an alternate rsync command
 synchronize: src=some/relative/path dest=/some/absolute/path rsync_path="sudo rsync"
 '''
@@ -90,7 +82,6 @@ def main():
         argument_spec = dict(
             src = dict(required=True),
             dest = dict(required=True),
-            verbosity = dict(default=0),
             delete = dict(default='no', type='bool'),
             private_key = dict(default=None),
             rsync_path = dict(default=None),
@@ -100,7 +91,6 @@ def main():
 
     source = module.params['src']
     dest = module.params['dest']
-    verbosity = module.params['verbosity']
     delete = module.params['delete']
     private_key = module.params['private_key']
     rsync_path = module.params['rsync_path']
@@ -109,10 +99,6 @@ def main():
     cmd = '%s --archive --delay-updates --compress' % rsync
     if module.check_mode:
         cmd = cmd + ' --dry-run'
-    if verbosity:
-        cmd = '%s -%s' % (cmd, 'v' * int(verbosity))
-    else:
-        cmd = cmd + ' --quiet'
     if delete:
         cmd = cmd + ' --delete-after'
     if private_key is None:
@@ -122,19 +108,18 @@ def main():
     cmd = cmd + " --rsh '%s %s -o %s'" % ('ssh', private_key,
                 'StrictHostKeyChecking=no')  # need ssh param
     if rsync_path:
-        cmd = cmd + ' --rsync-path ' + rsync_path
-
+        cmd = cmd + " --rsync-path '%s'" %(rsync_path)
+    changed_marker = '<<changed>>'
+    cmd = cmd + " --out-format='" + changed_marker + "%i %n%L'"
     cmd = ' '.join([cmd, source, dest])
     cmdstr = cmd
-    cmd = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE,
-                           stderr=subprocess.PIPE)
-    (out, err) = cmd.communicate()
-    if cmd.returncode:
-        return module.fail_json(msg=err, rc=cmd.returncode, cmd=cmdstr)
+    (rc, out, err) = module.run_command(cmd)
+    if rc:
+        return module.fail_json(msg=err, rc=rc, cmd=cmdstr)
     else:
-        return module.exit_json(changed=True, msg=out,
-                                rc=cmd.returncode, cmd=cmdstr, check=module.check_mode)
-
+        changed = changed_marker in out
+        return module.exit_json(changed=changed, msg=out.replace(changed_marker,''),
+                                rc=rc, cmd=cmdstr)
 
 # include magic from lib/ansible/module_common.py
 #<<INCLUDE_ANSIBLE_MODULE_COMMON>>