Rated 4 out of 5 stars
Very good. Liked it straight away even though I had to hunt around for the toolbar icon which is automatically added to the Navigation bar, which I have hidden.
One point that I don't like: you can't single click an icon to save what you have setup in the options - i.e. the visible region or the whole page. There IS a shortcut to do that, but I like to keep away from the keyboard.
Apart from that, it is really useful and will make it a lot easier to explain stuff to people by annotating a screen capture.