SignUpGenius has been the default volunteer sheet for fifteen years, and for a single potluck it still works. The trouble starts when one event needs more than one list.
A school musical needs rehearsal snacks, rides home, crew roles that have no date, and separate lists for each performance. A children's ministry needs the same four rooms covered every Sunday. A food pantry needs the same three shifts every week. In SignUpGenius each of those is its own sheet, with its own link, and a parent who wants to bring snacks on Tuesday and usher on Friday signs up twice and gets two emails.
What to look for instead
One link for the whole campaign. Every list on one page, so a volunteer sees everything they could do and picks from all of it.
One submission. Check off several things, enter a name and email once, get one confirmation with one link to change any of it.
No accounts for volunteers. The moment you ask a parent to create a login, a third of them stop.
No ads. Your volunteers should see your event, not a banner.
Availability first, for rotations. Children's ministry teams don't want first-come-first-served. They want volunteers to say which Sundays they can do, and a coordinator who assigns.
How JustSignup does it
JustSignup is built around one page, not a sheet. A page holds lists of three kinds: dated shifts, undated jobs, and things to bring with a quantity. Volunteers check things off across all of them and submit once. Pages can run first-come-first-served or collect availability for the coordinator to assign, with an auto-fill that spreads the load evenly.
Your first page is free to publish, with up to 30 volunteers, no ads, and no time limit, and it includes waitlists, reminders, calendar files and cancel links, the things SignUpGenius and SignUp.com sell as upgrades. Pro is $9 a month or $79 a year for groups that run several pages: unlimited volunteers, co-organizers, assigning, rolling schedules and hours reports. Cancel anytime.