I’ve been doing more flex testing, and my initial impression is it is faster than my expectations. I did at least 7 different K-means tests with it, and tried to implement some image processing algorithms including edge detection, gradients, blurring and it is not slow.
However, flex does not have multithreading, which makes 1. makes it harder to do longer processing 2. makes it impossible to distribute the load across CPU cores. As a result, I had to implement a timer that calls a function every small interval, and inside that function I broke my processing into smaller pieces, and had to implement several states and switch between them. It actually made my implementation much more difficult and more sophisticated. I hope that at one point Adobe will add multithreading.