The first thing I noticed is that on my MacBook Pro's screen, the written text is miniscule. True, for chapters, you can double click the chapter name and a new edit window pops up, allowing you to set the zoom level, but all the other windows don't seem to have the setting. My old, tired eyes have a hard time with this.

I set up a time line (one nifty feature) with a number of scenes - these are horizontal bars along a time line. A little later, after switching to another view and returning, all the scenes but one had disappeared. Closed the app and later opened it up again - lo and behold, the scenes reappeared. You can grab the bar and stretch or compact it, but sometimes, as the mouse moves left and right, the bar looses connection and begins moving at a different rate or just collapses. Definite problems here.

Overall, I just felt that the product didn't work with me, didn't fit like a glove. I've used Scrivener, and that seems very intuitive and responsive to me. StoryMill did not impress me.