The ease of creating custom shapes using the tool is fantastic! I can't think of anything that's not great about it, so far. It does take some practice to get used to how the tools work but once you do, they are incredibly intuitive. We use this program at my school with our students in Pre-K through 2nd grade. They love using the software and learn new skills as they go along. Using these programs helps kids understand basic math concepts like fractions, proportions, etc., while also having fun doing so.