Just had a deeper look at Max/Jitter. It's just incredible.
How does Jitter compare to GEM (or framestein which I never have used...)
Jitter is a one-in-all system (pixel, OpenGL, Quicktime) with a very general multi-dimensional multi-plane matrix formalism. It's extremely flexible, fast (much faster than NATO for example) and well-documented, and of course, all views can be embedded into the patcher which allows for very elaborated interfaces. It comes with an own SDK for external programming (which is not complete yet), which extends the normal Max object SDK. There is also a new extension to the normal object formalism in the form of "attributes" which can be set by messages (and also directly in the object command line) and also be queried (dumped out). In the next release of flext this feature will also be available for flext externals for PD.
greetings, Thomas