I enjoy both!! I like watching anime dubbed because I can actually better understand the story. On the other hand, its great to watch it subtitled in its original form, and reading what was originally intended.
On the other hand, many dubs tend to be edited (though not as much as it used to be), and because of it, many stories could be totally altered because of it. Either by bad voice acting (ex: VA's not portraying the character's personality correctly), or the voice they use themselves). Of course, English dubs have come a long way, and many VA's voices make many of the dubs for today's popular anime great.
As for subtitles, I have always had a hard time getting into a story when I just read words on the screen and I don't focus on the animation itself. Personally speaking, I have always been more visually-oriented and learn more by sight and touch, so, naturally, I prefer hearing the dub to reading the dialogue. Spending too much time reading words prevents me from getting as immersed in the story.
I could barely understand but a few of the most common Japanese words after watching subtitled anime, but that's relatively insiginficant when I want to fully understand watching an anime in it's original form as it was intended to be. If I take some Japanese courses in college and then I actually get to understand what anime characters are saying without the use of subtitles, that would totally make my day!!