To Outline or Not to Outline?

I've written 4 novels, one shorty story and working on a few other projects at this time. To date I've never outlined a novel. I guess I fall into that category of what this field calls a "panster."

I conjure up the idea for a novel, have certain scenes flash through my head and kind of fill in the spaces in between.

For the first time in my writing career, I actually sat down and completed an outline complete with character profiles and such.

I think there are benefits to both sides.

In completing my first outline ever, I like it that I can flip through and find important elements that I might have had the best intentions of writing down once I got home and then having not done it and then the material is forgotten and I'm left kicking myself.

However, there is a certain beauty in writing panster-style. You have a concept, a certain scene, and kind of allow your characters to help you navigate your way around the novel. In doing this, I actually came up with my third book. Black Atonement was never something I intended to do when I conceived the idea for the Vulcan Legacies. But around the middle of book 2, Black Abaddon, the future characters took on a story all their own and thus, book 3 was born.

Are you a plotter?

Are you a panster?

And whichever of the above category you fall into, why? What do you find beneficial about your writing style?