Does anyone have advice/suggestions/insight into these or other volunteer scheduling systems? I am testing out: Freehub, Flipcause, When I Work, Volgistics, and Freecyclerys rad spreadsheet. 

Right now we have no scheduling system, but rather operate with a "just show up at these times" system. Keyholders let me know when they can't be at their regularly scheduled program and then I cover. 

We have about 15 core volunteers (volunteer 4-6 time a month), and 15 active volunteers (they come once or twice a month). The main issue that I hope to resolve is volunteer retention and making all folks feel welcome to be a part of the organization. I realize there are many other benefits to implementing a scheduling system, as well as way to retain volunteers. 

Thank you in advance!