I've used (and paid for) this app for quite a while and have been VERY happy with it. However, this version (4.0.9) for OS X has a few problems. Generally it works great and I recommend it. However, I've had the following problemsÉ

When working with a folder full of images the "old" version for OS 9 would remember where you were in the file list so you could use keyboard shortcuts to open a picture, edit it, save it, and then go right to the next image in the directory. The OS X version doesn't do this which really cuts down on my editing speed.

When dealing with lots of images, one after the other, the app crashes and sometimes even takes OS X with it (which is the first time I've ever seen the retail version of OS X crash). I have 756MB RAM but it appear to be running out of memory and crashes.

When opening lots of images at the same time the app crashed and sometimes takes OS X along with it (see above).

When using the Convert option to do batch processes, the scroll bar on the right hand side will not always go active when you click in the file list. You can still navigate with the arrow keys butÉ

Anyway, I think these issues will be fixed shortly based on past experiences with Lemke Software. He/They have generally fixes bug quickly; as soon as they are identified. I still recommend this app; you won't find another that provides the feature set for anywhere near the same price.