I gave Evernote (for PC) a try just because. Guess what? I really do like it.
One of the things I want in writing software is a way to take an organize pieces of a story. Scrivener has a corkboard feature which is nice (so do a couple of other programs, like Celtx Plus) but I wasn't crazy about everything else it has. Also, I'm still trying out Scrivener and Celtx (not Plus) to see if they are worth paying for.
Evernote has two advantages that I could see right off the bat. First, it's very easy to get started with so I didn't need to spend hours and hours figuring out all the features. It will take some time for me to get completely comfortable with the entire package, but I can work with it as I learn. Second, it's free.
As far as the ability to visualize and organize a story, Evernote doesn't have a specific index card type feature. The way it's set up, though, it gives me the same benefit as a board. Kind of hard for me to untwist my brain enough this morning to explain, so:
|The "Cards" are in the middle pane|
|This is the "Index" view. The "Cards" are now shown as lists at the top.|
|This is the "Snippet" view|
Good luck with your projects.