Anyone use FastStone Image Viewer for PP (light, contrast, sharpness, etc)???

There's a lot of stuff in there on the left, looks highly technical, does anyone use it regularly?

I love the bits I do use, like viewing, comparing, straightening without losing sharpness, cropping, batch size reduction, etc.

And the Comparison thing is great for comparing pics side-by-side here on the Forum.

Mike