I love that 15Five offers free webinars on a monthly basis to help admins and user alike get acquainted with their product. Makes my life easier as we get into review season that i can share their review webinar with my employees instead of hosting my own orientation.
My company is highly engaged with their "high five" feature where one can give public praise and tag another person to let them know they are appreciated. We use the slack integrations too, so all company can view praise as it comes in.
Our weekly check ins via their platform give us an idea of how our employees are feeling overall and help us know where to zoom in and pay attention or take action. Easy to use, intuitive, user friendly, quick to fill out, and gives us much needed engagement data. Review collected by and hosted on G2.com.