Good news! The very first fully assembled ION servo drive boards have arrived. I jumped straight to programming the thing. Few parts of code have been already ported from Argon and everything has worked flawlessly so far.
The drive is equipped with ARM Cortex M4 processor with hardware floating point unit (FPU). I ran small test of FPU performance and found out that simple floating point arithmetic operations execute 20-30 times faster compared to non-FPU code. This means, all control code can be written with floating point math yielding ultimate precision and dynamic range without sacrificing servo bandwidth.