Functional, but lacking

It does what the images say it will … and nothing more.
You cannot set preferences for things like "always use Genva Font, with Midnight Blue for the colour" …. so EVERY time you type something in, you have to change font and color.
If you import a signature via an existing graphic, you cannot define the transparent color, so it never looks quite right.
You cannot add a public-key digital signature; just a graphic.
The "finger pad" for drawing your signature does not behave well in multimonitor set-ups; it seems to "need" to be on the main monitor, regardless of which screen the application is on.
Its OK. Can I use it for business? Yes. Was it a fun, well done user experience? No.

10NamesLater about Sign PDF, v1.6.0