Andy,

the ethernet option is out and so far is showing to be a bit of improvement over the USB in that you don't the grounding issue that some of the USB cables cause with the USB SS (smoothstepper). I don't have one yet and YET is the watch word there. Everything I have read on it in the different forums that have info on it says that it for al purposes brings Mach up to full speed (at 4Mhz you would expect that) and with 51 I/O options you would be hard put for us small shop users or a hobby CNC user to max out the inputs/outputs on a board.

Hope that helps a bit and good luck.

Michael