I do the majority of my writing with pen and paper. After reading an article the other day, I think it's something to do with disconnecting from everything-getting away from the computer and all that. The article was about why people tend to be more creative when in the shower or driving.
I used Word in the past, but don't have it anymore since I bought a Mac. I do have pages, but I use that pretty much for converting into formats readable on PCs and to copy to my iPad. I use Scrivener because it allows me to keep all my notes and everything in the one program, and it's extremely easy to keep everything together when I have a tendency to keep multiple copies of everything when I change stuff. The way I learned to use it was to take one of my older stories and import it. Then I started a new project and figured out more. Plus there are video tutorials.
I've heard with Word that there can be issues with crashing when you get huge files, plus I remember at one time, last year I think, I saw Jim tweet that he lost a couple chapters because of Windows updates, even with the Word automatic save.
And since I have an iPad, iPod, and iPhone, I've got lots of apps on those, too, though so far I haven't really used too many of them. Though that's more my issues with not writing much lately.