The digitizers in the current iPad models are not high-resolution enough to permit anything more than rudimentary drawings or large scribbles of text. Do not expect Tablet PC/OneNote-like performance at all.
That said, I like the Bamboo Stylus and that one seemed to be the best-regarded when I purchased it.
That said, I like the Bamboo Stylus and that one seemed to be the best-regarded when I purchased it.