It's lite, it's simple and you can start using it very quickly. No need for thinking. The UX is fantastic and it's very intuitive. I was looking for a tool like this for months and it does everything I need (very simple, black and white to the bone wireframes)!! If you're a lite user, you'll love it.
I don't like it when products hold be hostage with assets i created on them. I find it pretty low.
