A brilliant peace of software and must have for CG hobbyists!
Curvy's strongest point is it's drawing feature which has a semi-steep learning curve (get it? 'curve' ?). It's not so much instructions that needs to be studied, over and over, but management of the curve and drawing tools takes a while to 'stick.'
Once you get the hang of it, however, it's a lot of fun to play around in and even more so if you own a graphics tablet.
Obviously far more developed than the free Sculptris or MeshMixer; I've been playing in this app for about four years now and still learning something new each day.
When I have to whip up an illustration quick and don't have time to waste in box modelers - I turn here first.
There are some current fallbacks however but hopefully Simon will update those soon.
1. Bump doesn't work if using an older AMD video card.
2. The GUI and viewports are not near as customizable as I would like them to be nor will Curvy remember what you do mange to customize. (however standard four port is still included)
3. When using the Curvy map there seems to be no way to apply it to only parts of the model there for any imported textures apply to the whole model. I believe this can be circumvented even using the free version of Project Dogwaffle
Which Simon has implemented a link to in the Curvy menus.
Ultimately, however, this is by far my favorite 3D tool when it comes to 3D software outside of standard poly/vertix/edge manipulation.