My favorite thing about Doodle is the ease with which you are able to design something. I also like having the ability to find out when everybody is available.
I love the ability to send out a link and get a large group of people scheduled. The simplicity of the software makes it accessible even to our non-tech friendly staff.
I enjoyed it because it allowed me to be creative and I was able to save all of the work in which I did.
The only negative I can think of is that occasionally a recipient's email will block a Doodle poll.
I did encounter trouble when trying to set my availability. When I tried to give my schedule, I found it hard to pull down to occupy the whole time slot.