I think Futaba 4pk it's a copy of DX3R, anybody confirm it?
Obviously the design of 4PK it's more bulky and huge compared with Spektrum one, anyway i don't like so much these kind of radical designs like Nomadio instead of simplicity kinds.
But i didn't see in pictures if works only with 4AA cells, if their FSST system it's derived from DSM2 or its really as fast as, due i never use Futaba kinds before.