Encouragement looks very promising. However, I'm not going to recommend my client buy the Pro version yet since, at the moment, we can't get the free version to work. When we select a campaign and click "Quick Send", this error appears and the message isn't sent:
Fatal error: Call to undefined method Joomla\Registry\Registry::getValue() in /public_html/administrator/components/com_encouragement/models/encouragement.php on line 522
Any ideas? The site is running Joomla 3.3.4.