I have been slowly encouraging our pta to use volunteerspot for the last year or two and I find it very easy to use.. My friend's pta use signupgenius and they are very happy too. I have found that lots of people like the convenience of an online signup and ability to choose what shift/area they are working in and who they are working with too. It also takes some of the volunteer co-ordination hassles off the chairperson. The reminders and ability to easily send a mass thank you note at the end are awesome too!
I also like the group page on volunteerspot where you can have all your events on one link, although it is an annoying process to get to it. The volunteerspot link is always in our email signature, along with our website, facebook and twitter pages, so parents are able to find it from any email, and it is also on our website and promoted on our facebook page too.
If you are unsure of which to choose, do one event with one program and the next event with the other and see what works best for your group.
I've used both Volunteer Spot and Sign Up Genius, and have a preference for Sign Up Genius. My big beef with Volunteer Spot used to be that you couldn't see who else was volunteering at a certain time, but that has since been changed, so not an issue anymore. But Volunteer Spot does send me more emails than I would prefer to get--once you sign up to volunteer, you're in their database and get their promotional stuff. Sign Up Genius doesn't seem to do that to people. Also, you can customize the look of the sign up more with Sign Up Genius. So, for me the edge goes to Sign Up Genius.
We've used volunteerspot.com for several activities; as a volunteer (not a coordinator) I found it worked pretty well -- maybe more reminders than I need, personally, but not a big deal.
I was wondering if anyone has any feedback using VolunteerSpot<dot>com or SignUpGenius<dot>com? any pros/cons? Also did anyone find a different one from these two that they felt was a better tool?