Perhaps the most challenging part is figuring out where an option is employed and how it works (or doesn't). I did a lot of trial and error to get everything working as I liked. I also had to make some adjustments in my plans, so don't go into it with an all-or-nothing attitude.
One thing that I think could be better is that there are deeper side options where you can input html but the text box to enter them is very small. I found the best way to do this was to write them out first, then cut and paste them in.
When it came to customer support, these guys were great. They answered my questions, helped me understand which extension would work the best for me (I had started out with the very similar Survey Force), and have been very pleased with the operation of it overall.