I can confirm that the cost for trading EMD under TradeStation is $2.42 RT (round trip) vs about $4.70 RT for other CME stock index futures. You will need to be on the unbundled plan, which most newer accounts are. I am not sure about other brokerages such as IB who also have unbundled plans.
Apparently if you are on the bundled plans, the savings will not be passed on to you and your broker pockets the difference.
The only drawback to EMD is that the volume is thin. However, if you are trading 3-5 contracts at a time, there shouldn't be a problem and the savings could be significant, especially for a scalper.
The range spread is really not as bad as it looks by the indicator, it is fairly isolated to a single bar that usually has a greater ATR in the ER2 vs EMD, thus making EMD less jumpy in the aforementioned periods (usually opening and closing).
