Having spent the last month or so working with Processing 2b8, I can give my own reply to the question: *very*!
Essentially, don't depend on the OpenGL features in Processing 2.0. Although, the OpenGL bindings work it makes no additional use of the GPU and so the improvements are purely cosmetic with little improvements in performance.
Essentially, don't depend on the OpenGL features in Processing 2.0. Although, the OpenGL bindings work it makes no additional use of the GPU and so the improvements are purely cosmetic with little improvements in performance.