I'm actually writing my diploma thesis using Markdown and Pandoc. Some hacking is necessary (sed is so far sufficient), but it's a lot more pleasant then writing LaTeX directly.
I sometimes start writing papers in markdown using Pandoc too, but usually I eventually switch over to Latex when the formatting needs get more complicated. Still, it's a nice way to write. I love that Pandoc allows you to throw in arbitrary Latex markup wherever you want, easily allowing for math formulas and figure floats.
While I agree that it's faster, I'm not sure whether it's more pleasant. After you get all the styling info out of the way, LaTeX is pretty easy to write...
