I enjoyed using Powtoon. The interface is simple but offers a great deal of complexity, similar to the now-defunct xtranormal. I found GIMP fairly accessible as well, but there was one frustrating feature: the fact that all of the control tools are treated as separate windows meant that I had to click on each element to bring it to the front each time I wanted to switch back to GIMP from another application. There may be a more efficient way to do this, but it wasn't obvious and I didn't use the program enough to bother looking it up.
I enjoyed the class quite a bit. I learned a fair amount about various design media, I liked the interaction with the other students, and I created some designs that were better than what I thought I'd be able to come up with given my lack of experience. Thank you; it's been a pleasure.
