jat li or jackie chan???

[Grey Acumen]

It depends on whether you're talking about Jacki Chan's Early work or his late work. Fearless Hyena is still in my top favorite martial artist movie of all time, and I marveled at the stunt work he did, cause it showed that it was real. Controlled, but utterly real.
Recently though, there has been more special effects, 3d work and wire use in his movies, and lets face it, he's over 50 now. After the stuff he's done, he totally deserves to start taking it easy.

I haven't seen much of Jet Li's work, but like Legend11 pointed out, there's a huge difference between a dramatic actor and a comedic actor. I personally value comedy much more highly than drama, as the world already has enough drama already, we need the laughs.