I tend to read a lot more manga simply because a) I love comic books in general, and b) it takes a lot less time to read a few chapters of a manga than it does to watch an equivalent amount of anime.
Sub vs Dub:
The days of god awful dubbing are long gone for the most part. This isn't the 90s. Dubbing has gotten a lot better over the years, to the point where I sometimes think the english voice acting is better than the japanese.
That being said, even if I do watch the dub I'll usually watch it with the subtitles on as well, given the option. The dubs tend to change or leave out things that don't fit well into the pacing of the dialog. It's usually not anything major but it's still interesting to see the differences.