I am evaluating the trial version right now. One important thing that the publisher acknowledges himself : in its present version, Scrivener is not high DPI aware. This means that if, for instance, you have a modern laptop with a comparatively small screen but a high resolution, or if, like me, you have a 24″ monitor with a regular 1920 x 1200, but have set Windows 7 to display at 150 %, the user interface fonts and icons may be to small to use. Supposedly, this will be corrected at some point in the future.
I was able to alleviate the problem, up to a point, by changing font sizes in the Preferences menu, but your situation might be different. I highly recommend downloading the trial version first, in order to be sure. It’s a generous offer, since it’s fully functional and limited to 30 days, but that’s 30 days where you have actually launched the software to probe it, not 30 calendar days.
The manual is very good, and there are thorough video tours, too. Combined with the trial version, it’s a very good way to understand if this quite unique program is tailored to your needs. I has a way of doing things that is quite different from Word-like applications. It also takes more time than might be expected in order to fully understand the method. The time investment is worth it if your work entails a lot of writing, whether you decide to take the plunge or not. The Scrivener community seems very helpful.