Bad news is that if you want to use twin motors on X (or even if you want to allow for upgrading to two motors in the future), then as far as I can see you need the very expensive CS Labs board, the IP-S, not the IP-M. Have I understood this correctly? The ESS seems to be a reasonable choice - as long as you never need manufacturer support, and the PLCM kit is great if you read Russian! Not sure of the status of the E4, and the E3 needs a BOB, as does the ESS. This all makes choice of a driver trivial by comparison...