I never liked ES because I could never work a bid or offer. I was looking at the volume on ER2, and it is more than YM, hasn't passed NQ or ES yet. You can see the momentum block trades on ER2, whereas ES there are so many block trades it is harder to tell. I would think XLE would be easier to trade because you can jump into a trend before its over, whereas IWM and the other indices most of the time you see quick breakouts that have 50% of the move over 1-3min. I like ER2 over ES,NQ, YM, because the commission/payout is about 2x as good. If I sell for 1 tick up I get a little over $5/contract including the commision Round trip, whereas the other futures you only get like 2 cents for selling 1 tick up after commission is taken into account. If I had a choice between IWM and ER2, I would go with ER2.